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Table of Contents

1. SDLC and development guidelines
2. PCI DSS (Credit/Debit Card Handling) in applications
3. Infrastructure hardening (IIS, Apache, Windows)
4. Password policies
5. General security best practices
6. Interfaces
7. API Security Checklist
8. What are some proven application security principles?

SDLC and development guidelines

The OWASP Top 10 - 2013 includes the following changes as compared to the 2010 edition:

• Authentication controls (passwords, account lockouts, password resets, forgotten passwords, etc.)

• Authorisation controls (Access Restrictions)

• A2 Broken Authentication and Session Management (was formerly 2010-A3)

• Session Management

  • Session ID Properties: In order to keep the authenticated state and track the users progress within the web application, applications provide users with a session identifier (session ID or token) that is assigned at session creation time, and is shared and exchanged by the user and the web application for the duration of the session (it is sent on every HTTP request). The session ID is a “name=value” pair.

• Session ID Name Fingerprinting

  • The name used by the session ID should not be extremely descriptive nor offer unnecessary details about the purpose and meaning of the ID.
  • The session ID names used by the most common web application development frameworks can be easily fingerprinted [0], such as PHPSESSID (PHP), JSESSIONID (J2EE), CFID & CFTOKEN (ColdFusion), ASP.NET_SessionId (ASP .NET), etc. Therefore, the session ID name can disclose the technologies and programming languages used by the web application.
  • It is recommended to change the default session ID name of the web development framework to a generic name, such as “id”.

• Session ID Length: The session ID must be long enough to prevent brute force attacks, where an attacker can go through the whole range of ID values and verify the existence of valid sessions.

  • The session ID length must be at least 128 bits (16 bytes).
  • Session ID Entropy: The session ID must be unpredictable (random enough) to prevent guessing attacks, where an attacker is able to guess or predict the ID of a valid session through statistical analysis techniques. For this purpose, a good PRNG (Pseudo Random Number Generator) must be used. The session ID value must provide at least 64 bits of entropy (if a good PRNG is used, this value is estimated to be half the length of the session ID).

• Session ID Content (or Value): The session ID content (or value) must be meaningless to prevent information disclosure attacks, where an attacker is able to decode the contents of the ID and extract details of the user, the session, or the inner workings of the web application.

• Session Management Implementation

• Built-in Session Management Implementations: The storage capabilities or repository used by the session management mechanism to temporarily save the session IDs must be secure, protecting the session IDs against local or remote accidental disclosure or unauthorized access.

• Used vs. Accepted Session ID Exchange Mechanisms: A web application should make use of cookies for session ID exchange management. If a user submits a session ID through a different exchange mechanism, such as a URL parameter, the web application should avoid accepting it as part of a defensive strategy to stop session fixation.

• Transport Layer Securityn order to protect the session ID exchange from active eavesdropping and passive disclosure in the network traffic, it is mandatory to use an encrypted HTTPS (SSL/TLS) connection for the entire web session, not only for the authentication process where the user credentials are exchanged.

• The following set of HTTPS (SSL/TLS) best practices are focused on protecting the session ID (specifically when cookies are used) and helping with the integration of HTTPS within the web application:

  • Web applications should never switch a given session from HTTP to HTTPS, or viceversa, as this will disclose the session ID in the clear through the network.
  • Web applications should not mix encrypted and unencrypted contents (HTML pages, images, CSS, Javascript files, etc) on the same host (or even domain - see the “domain” cookie attribute), as the request of any web object over an unencrypted channel might disclose the session ID.
  • Web applications, in general, should not offer public unencrypted contents and private encrypted contents from the same host. It is recommended to instead use two different hosts, such as www.example.com over HTTP (unencrypted) for the public contents, and secure.example.com over HTTPS (encrypted) for the private and sensitive contents (where sessions exist). The former host only has port TCP/80 open, while the later only has port TCP/443 open.
  • Web applications should avoid the extremely common HTTP to HTTPS redirection on the home page (using a 30x HTTP response), as this single unprotected HTTP request/response exchange can be used by an attacker to gather (or fix) a valid session ID.
  • Web applications should make use of “HTTP Strict Transport Security (HSTS)” (previously called STS) to enforce HTTPS connections.

• Input/Data validation (XSS, SQL injections, XML injections, client side and server side validations, etc)

• Encryption (storage, transmission)

• Application server hardening (IIS, Apache)

• Use of CAPTCHA

• Logging for user actions and protection of logs

• A1 Injection

• A3 Cross-Site Scripting (XSS) (was formerly 2010-A2)

• A4 Insecure Direct Object References

• A5 Security Misconfiguration (was formerly 2010-A6)

• A6 Sensitive Data Exposure (2010-A7 Insecure Cryptographic Storage and 2010-A9 Insufficient Transport Layer Protection were merged to form 2013-A6)

• A7 Missing Function Level Access Control (renamed/broadened from 2010-A8 Failure to Restrict URL Access)

• A8 Cross-Site Request Forgery (CSRF) (was formerly 2010-A5)

• A9 Using Components with Known Vulnerabilities (new but was part of 2010-A6 – Security Misconfiguration)

• A10 Unvalidated Redirects and Forwards

PCI DSS (Credit/Debit Card Handling) in applications

Essentially, requirements 3, 4, 6, 8, 10 of the PCI DSS Standard version 3.1

Requirement 3: Protect stored cardholder data

• 3.1 - Keep cardholder data storage to a minimum by implementing data retention and disposal policies, procedures and processes that include at least the following for all cardholder data (CHD) storage:
  • Limiting data storage amount and retention time to that which is required for legal, regulatory, and/or business requirements
  • Specific retention requirements for cardholder data
  • Processes for secure deletion of data when no longer needed
  • A quarterly process for identifying and securely deleting stored cardholder data that exceeds defined retention.
• 3.1a - Examine the data retention and disposal policies, procedures and processes to verify they include the following for all cardholder data (CHD) storage: Limiting data storage amount and retention time to that which is required for legal, regulatory, and/or business requirements. Specific requirements for retention of cardholder data (for example, cardholder data needs to be held for X period for Y business reasons). Processes for secure deletion of cardholder data when no longer needed for legal, regulatory, or business reasons. A quarterly process for identifying and securely deleting stored cardholder data that exceeds defined retention requirements.
• 3.1c - For a sample of system components that store cardholder data: Examine files and system records to verify that the data stored does not exceed the requirements defined in the data retention policy
  • Observe the deletion mechanism to verify data is deleted securely.
• 3.2 - Do not store sensitive authentication data after authorization (even if encrypted). If sensitive authentication data is received, render all data unrecoverable upon completion of the authorization process.
• 3.2.1 - Do not store the full contents of any track (from the magnetic stripe located on the back of a card, equivalent data contained on a chip, or elsewhere) after authorization. This data is alternatively called full track, track, track 1, track 2, and magneticstripe data.
• 3.2.2 - Do not store the card verification code or value (three-digit or four-digit number printed on the front or back of a payment card used to verify card-notpresent transactions) after authorization.
• 3.2.3 - Do not store the personal identification number (PIN) or the encrypted PIN block after authorization.
• 3.3 - Mask PAN when displayed (the first six and last four digits are the maximum number of digits to be displayed), such that only personnel with a legitimate business need can see the full PAN
• 3.3a - Examine written policies and procedures for masking the display of PANs to verify:
  • A list of roles that need access to displays of full PAN is documented, together with a legitimate business need for each role to have such access.
  • PAN must be masked when displayed such that only personnel with a legitimate business need can see the full PAN.
  • All other roles not specifically authorized to see the full PAN must only see masked PANs.
• 3.3b - Examine system configurations to verify that full PAN is only displayed for users/roles with a documented business need, and that PAN is masked for all other requests.
• 3.3c - Examine displays of PAN (for example, on screen, on paper receipts) to verify that PANs are masked when displaying cardholder data, and that only those with a legitimate business need are able to see full PAN.
• 3.4 - Render PAN unreadable anywhere it is stored (including on portable digital media, backup media, and in logs) by using any of the following approaches: One-way hashes based on strong cryptography, (hash must be of the entire PAN) Truncation (hashing cannot be used to replace the truncated segment of PAN) Index tokens and pads (pads must be securely stored) Strong cryptography with associated key-management processes and procedures.
• 3.4.1 - If disk encryption is used (rather than file- or column-level database encryption), logical access must be managed separately and independently of native operating system authentication and access control mechanisms (for example, by not using local user account databases or general network login credentials). Decryption keys must not be associated with user accounts.
• 3.5 - Examine key-management policies and procedures to verify processes are specified to protect keys used for encryption of cardholder data against disclosure and misuse and include at least the following: Access to keys is restricted to the fewest number of custodians necessary. Key-encrypting keys are at least as strong as the dataencrypting keys they protect. Key-encrypting keys are stored separately from dataencrypting keys. Keys are stored securely in the fewest possible locations and forms.
• 3.5.1 - Examine user access lists to verify that access to keys is restricted to the fewest number of custodians necessary.
• 3.5.2 - Examine documented procedures to verify that cryptographic keys used to encrypt/decrypt cardholder data must only exist in one (or more) of the following forms at all times. Encrypted with a key-encrypting key that is at least as strong as the data-encrypting key, and that is stored separately from the data-encrypting key Within a secure cryptographic device (such as a hardware (host) security module (HSM) or PTS-approved point-of-interaction device)
• 3.5.2b - Examine system configurations and key storage locations to verify that cryptographic keys used to encrypt/decrypt cardholder data exist in one (or more) of the following form at all times. Encrypted with a key-encrypting key Within a secure cryptographic device (such as a hardware (host) security module (HSM) or PTS-approved point-of-interaction device)
• 3.5.3 - Store cryptographic keys in the fewest possible locations.
• 3.6.a Additional testing procedure for service provider assessments only: If the service provider shares keys with their customers for transmission or storage of cardholder data, examine the documentation that the service provider provides to their customers to verify that it includes guidance on how to securely transmit, store, and update customers’ keys, in accordance with Requirements 3.6.1 through 3.6.8 below.
• 3.6.1.a Verify that key-management procedures specify how to generate strong keys.
• 3.6.1.b Observe the method for generating keys to verify that strong keys are generated.
• 3.6.2.a Verify that key-management procedures specify how to securely distribute keys.
• 3.6.2.b Observe the method for distributing keys to verify that keys are distributed securely.
• 3.6.3.a Verify that key-management procedures specify how to securely store keys.
• 3.6.3.b Observe the method for storing keys to verify that keys are stored securely.
• 3.6.5.a Verify that key-management procedures specify processes for the following: The retirement or replacement of keys when the integrity of the key has been weakened The replacement of known or suspected compromised keys. Any keys retained after retiring or replacing are not used for encryption operations
• 3.6.6.a Verify that manual clear-text key-management procedures specify processes for the use of the following: Split knowledge of keys, such that key components are under the control of at least two people who only have knowledge of their own key components; AND Dual control of keys, such that at least two people are required to perform any key-management operations and no one person has access to the authentication materials (for example, passwords or keys) of another
• 3.6.7.a Verify that key-management procedures specify processes to prevent unauthorized substitution of keys

Requirement 4: Encrypt transmission of cardholder data across open, public networks

• 4.1 Use strong cryptography and security protocols (for example, TLS, IPSEC, SSH, etc.) to safeguard sensitive cardholder data during transmission over open, public networks, including the following:
  • Only trusted keys and certificates are accepted.
  • The protocol in use only supports secure versions or configurations.
  • The encryption strength is appropriate for the encryption methodology in use.
• 4.1.c Select and observe a sample of inbound and outbound transmissions as they occur to verify that all cardholder data is encrypted with strong cryptography during transit.
• 4.1.d Examine keys and certificates to verify that only trusted keys and/or certificates are accepted.
• 4.1.g For TLS implementations, examine system configurations to verify that TLS is enabled whenever cardholder data is transmitted or received. For example, for browser-based implementations:
  • “HTTPS” appears as the browser Universal Record Locator (URL) protocol, and
  • Cardholder data is only requested if “HTTPS” appears as part of the URL.
• 4.1.i For all other environments using SSL and/or early TLS: Review the documented Risk Mitigation and Migration Plan to verify it includes:
  • Description of usage, including what data is being transmitted, types and number of systems that use and/or support SSL/early TLS, type of environment;
  • Risk-assessment results and risk-reduction controls in place;
  • Description of processes to monitor for new vulnerabilities associated with SSL/early TLS;
  • Description of change control processes that are implemented to ensure SSL/early TLS is not implemented into new environments;
  • Overview of migration project plan including target migration completion date no later than June 30, 2016
• 4.2.a If end-user messaging technologies are used to send cardholder data, observe processes for sending PAN and examine a sample of outbound transmissions as they occur to verify that PAN is rendered unreadable or secured with strong cryptography whenever it is sent via end-user messaging technologies.
• 4.2.b Review written policies to verify the existence of a policy stating that unprotected PANs are not to be sent via end-user messaging technologies.

Requirement 6: Develop and maintain secure systems and applications

• 6.1.a Examine policies and procedures to verify that processes are defined for the following: * [ ] To identify new security vulnerabilities * [ ] To assign a risk ranking to vulnerabilities that includes identification of all “high risk” and “critical” vulnerabilities. * [ ] To use reputable outside sources for security vulnerability information.
• 6.2.a Examine policies and procedures related to securitypatch installation to verify processes are defined for: * [ ] Installation of applicable critical vendor-supplied security patches within one month of release. * [ ] Installation of all applicable vendor-supplied security patches within an appropriate time frame (for example, within three months).
• 6.2.b For a sample of system components and related software, compare the list of security patches installed on each system to the most recent vendor security-patch list, to verify the following: * [ ] That applicable critical vendor-supplied security patches are installed within one month of release. * [ ] All applicable vendor-supplied security patches are installed within an appropriate time frame (for example, within three months).
• 6.3.a Examine written software-development processes to verify that the processes are based on industry standards and/or best practices.
• 6.3.b Examine written software-development processes to verify that information security is included throughout the life cycle.
• 6.3.c Examine written software-development processes to verify that software applications are developed in accordance with PCI DSS.
• 6.3.1 Examine written software-development procedures and interview responsible personnel to verify that preproduction and/or custom application accounts, user IDs and/or passwords are removed before an application goes into production or is released to customers.
• 6.3.2.a Examine written software-development procedures and interview responsible personnel to verify that all custom application code changes must be reviewed (using either manual or automated processes) as follows:
  • Code changes are reviewed by individuals other than the originating code author, and by individuals who are knowledgeable in code-review techniques and secure coding practices.
  • Code reviews ensure code is developed according to secure coding guidelines (see PCI DSS Requirement 6.5).
  • Appropriate corrections are implemented prior to release.
  • Code-review results are reviewed and approved by management prior to release.
• 6.4 Examine policies and procedures to verify the following are defined:
  • Development/test environments are separate from production environments with access control in place to enforce separation.
  • A separation of duties between personnel assigned to the development/test environments and those assigned to the production environment.
  • Production data (live PANs) are not used for testing or development.
  • Test data and accounts are removed before a production system becomes active.
  • Change control procedures related to implementing security patches and software modifications are documented.
• 6.4.1.a Examine network documentation and network device configurations to verify that the development/test environments are separate from the production environment(s)
• 6.4.1.b Examine access controls settings to verify that access controls are in place to enforce separation between the development/test environments and the production environment(s).
• 6.4.3.a Observe testing processes and interview personnel to verify procedures are in place to ensure production data (live PANs) are not used for testing or development.
• 6.4.4.a Observe testing processes and interview personnel to verify test data and accounts are removed before a production system becomes active.
• 6.4.5.a Examine documented change control procedures related to implementing security patches and software modifications and verify procedures are defined for:
  • Documentation of impact
  • Documented change approval by authorized parties
  • Functionality testing to verify that the change does not adversely impact the security of the system
  • Back-out procedures
• 6.4.5.2 Verify that documented approval by authorized parties is present for each sampled change.
• 6.4.5.3.a For each sampled change, verify that functionality testing is performed to verify that the change does not adversely impact the security of the system.
• 6.4.5.3.b For custom code changes, verify that all updates are tested for compliance with PCI DSS Requirement 6.5 before being deployed into production
• 6.4.5.4 Verify that back-out procedures are prepared for each sampled change.
• 6.5.a Examine software-development policies and procedures to verify that training in secure coding techniques is required for developers, based on industry best practices and guidance.
• 6.5.c Examine records of training to verify that software developers received training on secure coding techniques, including how to avoid common coding vulnerabilities, and understanding how sensitive data is handled in memory.
  • [ ]
• 6.5.1 Injectionflaws, especially SQL - Examine software-development policies and procedures and interview responsible personnel to verify that injection flaws are addressed by coding techniques that include:
  • Validating input to verify user data cannot modify meaning of commands and queries.
  • Utilizing parameterized queries.
• 6.5.2 Buffer overflows - Examine software-development policies and procedures and interview responsible personnel to verify that buffer overflows are addressed by coding techniques that include:
  • Validating buffer boundaries.
  • Truncating input strings.
• 6.5.3 Insecure cryptographic storage Examine software-development policies and procedures and interview responsible personnel to verify that insecure cryptographic storage is addressed by coding techniques that: * [ ] Prevent cryptographic flaws. * [ ] * [ ] Use strong cryptographic algorithms and keys.
• 6.5.4 Insecure communications - Examine software-development policies and procedures and interview responsible personnel to verify that insecure communications are addressed by coding techniques that properly authenticate and encrypt all sensitive communications.
• 6.5.5 Improper error handling - Examine software-development policies and procedures and interview responsible personnel to verify that improper error handling is addressed by coding techniques that do not leak information via error messages (for example, by returning generic rather than specific error details).
• 6.5.6 Examine software-development policies and procedures and interview responsible personnel to verify that coding techniques address any “high risk” vulnerabilities that could affect the application, as identified in PCI DSS Requirement 6.1.
• 6.5.7 Cross-site scripting (XSS) - Examine software-development policies and procedures and interview responsible personnel to verify that cross-site scripting (XSS) is addressed by coding techniques that include
  • Validating all parameters before inclusion
  • Utilizing context-sensitive escaping.
• 6.5.8 Improper access control (such as insecure direct object references, failure to restrict URL access, directory traversal, and failure to restrict user access to functions). Examine software-development policies and procedures and interview responsible personnel to verify that improper access control—such as insecure direct object references, failure to restrict URL access, and directory traversal—is addressed by coding technique that includes:
  • Proper authentication of users
  • Sanitizing input
  • Not exposing internal object references to users
  • User interfaces that do not permit access to unauthorized functions.
• 6.5.9 Cross-site request forgery (CSRF) - Examine software development policies and procedures and interview responsible personnel to verify that cross-site request forgery (CSRF) is addressed by coding techniques that ensure applications do not rely on authorization credentials and tokens automatically submitted by browsers.
• 6.5.10 Broken authentication and session managementNote: Requirement 6.5.10 is a best practice until June 30, 2015, after which it becomes a requirement. 6.5.10 Examine software development policies and procedures and interview responsible personnel to verify that broken authentication and session management are addressed via coding techniques that commonly include:
  • Flagging session tokens (for example cookies) as “secure”
  • Not exposing session IDs in the URL
  • Incorporating appropriate time-outs and rotation of session IDs after a successful login
• 6.6 For public-facing web applications, ensure that either one of the following methods is in place as follows:
  • Examine documented processes, interview personnel, and examine records of application security assessments to verify that public-facing web applications are reviewed—using either manual or automated vulnerability security assessment tools or methods—as follows: - At least annually - After any changes - By an organization that specializes in application security - That, at a minimum, all vulnerabilities in Requirement 6.5 are included in the assessment - That all vulnerabilities are corrected - That the application is re-evaluated after the corrections.
  • Examine the system configuration settings and interview responsible personnel to verify that an automated technical solution that detects and prevents web-based attacks (for example, a web-application firewall) is in place as follows: - Is situated in front of public-facing web applications to detect and prevent web-based attacks. - Is actively running and up to date as applicable. - Is generating audit logs. - Is configured to either block web-based attacks, or generate an alert that is immediately investigated.
• 6.7 Examine documentation and interview personnel to verify that security policies and operational procedures for developing and maintaining secure systems and applications are:
  • Documented,
  • In use, and
  • Known to all affected parties.

Requirement 8: Identify and authenticate access to system components

• 8.1.1 Assign all users a unique ID before allowing them to access system components or cardholder data.
• 8.1.2 Control addition, deletion, and modification of user IDs, credentials, and other identifier objects.
• 8.1.3 Immediately revoke access for any terminated users.
• 8.1.3.b Verify all physical authentication methods—such as, smart cards, tokens, etc.—have been returned or deactivated.
• 8.1.4 Remove/disable inactive user accounts within 90 days.
• 8.1.5 Manage IDs used by vendors to access, support, or maintain system components via remote access as follows:
  • Enabled only during the time period needed and disabled when not in use.
  • Monitored when in use.
• 8.1.6 Limit repeated access attempts by locking out the user ID after not more than six attempts.
• 8.1.7 Set the lockout duration to a minimum of 30 minutes or until an administrator enables the user ID.
• 8.1.8 If a session has been idle for more than 15 minutes, require the user to re-authenticate to re-activate the terminal or session.
• 8.2 In addition to assigning a unique ID, ensure proper user-authentication management for non-consumer users and administrators on all system components by employing at least one of the following methods to authenticate all users:
  • Something you know, such as a password or passphrase
  • Something you have, such as a token device or smart card
  • Something you are, such as a biometric.
• 8.2.1 Using strong cryptography, render all authentication credentials (such as passwords/phrases) unreadable during transmission and storage on all system components.
• 8.2.2 Verify user identity before modifying any authentication credential—for example, performing password resets, provisioning new tokens, or generating new keys.
• 8.2.3 Passwords/phrases must meet the following:  Require a minimum length of at least seven characters.  Contain both numeric and alphabetic characters. Alternatively, the passwords/phrases must have complexity and strength at least equivalent to the parameters specified above.
• 8.2.4 Change user passwords/passphrases at least once every 90 days.
• 8.2.5 Do not allow an individual to submit a new password/phrase that is the same as any of the last four passwords/phrases he or she has used.
• 8.2.6 Set passwords/phrases for firsttime use and upon reset to a unique value for each user, and change immediately after the first use.
• 8.3 Incorporate two-factor authentication for remote network access originating from outside the network by personnel (including users and administrators) and all third parties, (including vendor access for support or maintenance).
• 8.4 Document and communicate authentication policies and procedures to all users including:
  • Guidance on selecting strong authentication credentials
  • Guidance for how users should protect their authentication credentials
  • Instructions not to reuse previously used passwords
  • Instructions to change passwords if there is any suspicion the password could be compromised.
• 8.5 Do not use group, shared, or generic IDs, passwords, or other authentication methods as follows:
  • Generic user IDs are disabled or removed.
  • Shared user IDs do not exist for system administration and other critical functions.
  • Shared and generic user IDs are not used to administer any system components.
• 8.5.1 Additional requirement for service providers only: Service providers with remote access to customer premises (for example, for support of POS systems or servers) must use a unique authentication credential (such as a password/phrase) for each customer.
• 8.6 Where other authentication mechanisms are used (for example, physical or logical security tokens, smart cards, certificates, etc.), use of these mechanisms must be assigned as follows:
  • Authentication mechanisms must be assigned to an individual account and not shared among multiple accounts.
  • Physical and/or logical controls must be in place to ensure only the intended account can use that mechanism to gain access.
• 8.7 All access to any database containing cardholder data (including access by applications, administrators, and all other users) is restricted as follows:
  • All user access to, user queries of, and user actions on databases are through programmatic methods.
  • Only database administrators have the ability to directly access or query databases.
  • Application IDs for database applications can only be used by the applications (and not by individual users or other non-application processes).
• 8.8 Ensure that security policies and operational procedures for identification and authentication are documented, in use, and known to all affected parties.

Requirement 10: Track and monitor all access to network resources and cardholder data

• 10.1 Implement audit trails to link all access to system components to each individual user.
• 10.2 Implement automated audit trails for all system components to reconstruct the following events:
  • 10.2.1 All individual user accesses to cardholder data
  • 10.2.2 All actions taken by any individual with root or administrative privileges
  • 10.2.3 Access to all audit trails
  • 10.2.4 Invalid logical access attempts
  • 10.2.5 Use of and changes to identification and authentication mechanisms—including but not limited to creation of new accounts and elevation of privileges—and all changes, additions, or deletions to accounts with root or administrative privileges
  • 10.2.6 Initialization, stopping, or pausing of the audit logs
  • 10.2.7 Creation and deletion of systemlevel objects
• 10.3 Record at least the following audit trail entries for all system components for each event:
  • 10.3.1 User identification
  • 10.3.2 Type of event
  • 10.3.3 Date and time
  • 10.3.4 Success or failure indication
  • 10.3.5 Origination of event
  • 10.3.6 Identity or name of affected data, system component, or resource.
• 10.4 Using time-synchronization technology, synchronize all critical system clocks and times and ensure that the following is implemented for acquiring, distributing, and storing time.
  • 10.4.1 Critical systems have the correct and consistent time.
  • 10.4.2 Time data is protected.
  • 10.4.3 Time settings are received from industry-accepted time sources.
• 10.5 Secure audit trails so they cannot be altered.
  • 10.5.1 Limit viewing of audit trails to those with a job-related need.
  • 10.5.2 Protect audit trail files from unauthorized modifications.
  • 10.5.3 Promptly back up audit trail files to a centralized log server or media that is difficult to alter.
  • 10.5.4 Write logs for external-facing technologies onto a secure, centralized, internal log server or media device.
  • 10.5.5 Use file-integrity monitoring or change-detection software on logs to ensure that existing log data cannot be changed without generating alerts (although new data being added should not cause an alert).
• 10.6 Review logs and security events for all system components to identify anomalies or suspicious activity.
  • 10.6.1 Review the following at least daily:
  • All security events
  • Logs of all system components that store, process, or transmit CHD and/or SAD
  • Logs of all critical system components
  • Logs of all servers and system components that perform security functions (for example, firewalls, intrusion-detection systems/intrusion-prevention systems (IDS/IPS), authentication servers, e-commerce redirection servers, etc.).
  • 10.6.2 Review logs of all other system components periodically based on the organization’s policies and risk management strategy, as determined by the organization’s annual risk assessment.
• 10.6.3 Follow up exceptions and anomalies identified during the review process.
• 10.7 - Retain audit trail history for at least one year, with a minimum of three months immediately available for analysis (for example, online, archived, or restorable from backup)
• 10.8 - Ensure that security policies and operational procedures for monitoring all access to network resources and cardholder data are documented, in use, and known to all affected parties. https://www.pcisecuritystandards.org/documents/PCI_DSS_v3-1.pdf

Infrastructure hardening (IIS, Apache, Windows)

Review and implement hardening standards available at www.cisecurity.org

Password policies

For users:

Minimum 8 characters Complexity set requiring a combination of letters, numbers and optional special characters Account locked for at least 30 mins after 5 incorrect attempts

For administrators:

Minimum 12 characters Complexity set requiring a combination of letters, numbers and special characters Account locked out indefinitely until unlocked after 5 incorrect attempts

General security best practices

SO 27001 Annex A Controls (apply the ones applicable and where a risk exists)

Interfaces

Restriction by IP Address

API Security Checklist

Checklist of the most important security countermeasures when designing, testing, and releasing your API.

Authentication

• Don't use Basic Auth Use standard authentication (e.g. JWT, OAuth).
• Don't reinvent the wheel in Authentication, token generation, password storage. Use the standards.
• Use Max Retry and jail features in Login.
• Use encryption on all sensitive data.

JWT (JSON Web Token)

• Use a random complicated key (JWT Secret) to make brute forcing the token very hard.
• Don't extract the algorithm from the payload. Force the algorithm in the backend (HS256 or RS256).
• Make token expiration (TTL, RTTL) as short as possible.
• Don't store sensitive data in the JWT payload, it can be decoded easily.

OAuth

• Always validate redirect_uri server-side to allow only whitelisted URLs.
• Always try to exchange for code and not tokens (don't allow response_type=token).
• Use state parameter with a random hash to prevent CSRF on the OAuth authentication process.
• Define the default scope, and validate scope parameters for each application.

Access

• Limit requests (Throttling) to avoid DDoS / brute-force attacks.
• Use HTTPS on server side to avoid MITM (Man In The Middle Attack).
• Use HSTS header with SSL to avoid SSL Strip attack.

Input

• Use the proper HTTP method according to the operation: GET (read), POST (create), PUT/PATCH (replace/update), and DELETE (to delete a record), and respond with 405 Method Not Allowed if the requested method isn't appropriate for the requested resource.
• Validate content-type on request Accept header (Content Negotiation) to allow only your supported format (e.g. application/xml, application/json, etc) and respond with 406 Not Acceptable response if not matched.
• Validate content-type of posted data as you accept (e.g. application/x-www-form-urlencoded, multipart/form-data, application/json, etc).
• Validate User input to avoid common vulnerabilities (e.g. XSS, SQL-Injection, Remote Code Execution, etc).
• Don't use any sensitive data (credentials, Passwords, security tokens, or API keys) in the URL, but use standard Authorization header.
• Use an API Gateway service to enable caching, Rate Limit policies (e.g. Quota, Spike Arrest, Concurrent Rate Limit) and deploy APIs resources dynamically.

Processing

• Check if all the endpoints are protected behind authentication to avoid broken authentication process.
• User own resource ID should be avoided. Use /me/orders instead of /user/654321/orders.
• Don't auto-increment IDs. Use UUID instead.
• If you are parsing XML files, make sure entity parsing is not enabled to avoid XXE (XML external entity attack).
• If you are parsing XML files, make sure entity expansion is not enabled to avoid Billion Laughs/XML bomb via exponential entity expansion attack.
• Use a CDN for file uploads.
• If you are dealing with huge amount of data, use Workers and Queues to process as much as possible in background and return response fast to avoid HTTP Blocking.
• Do not forget to turn the DEBUG mode OFF.

Output

• Send X-Content-Type-Options: nosniff header.
• Send X-Frame-Options: deny header.
• Send Content-Security-Policy: default-src 'none' header.
• Remove fingerprinting headers - X-Powered-By, Server, X-AspNet-Version etc.
• Force content-type for your response, if you return application/json then your response content-type is application/json.
• Don't return sensitive data like credentials, Passwords, security tokens.
• Return the proper status code according to the operation completed. (e.g. 200 OK, 400 Bad Request, 401 Unauthorized, 405 Method Not Allowed, etc).

CI & CD

• Audit your design and implementation with unit/integration tests coverage.
• Use a code review process and disregard self-approval.
• Ensure that all components of your services are statically scanned by AV software before push to production, including vendor libraries and other dependencies.
• Design a rollback solution for deployments.

What are some proven application security principles?

• Apply defense in depth (complete mediation)
• Use a positive security model (fail-safe defaults, minimize attack surface)
• Fail securely
• Run with least privilege
• Avoid security by obscurity (open design)
• Keep security simple (verifiable, economy of mechanism)
• Detect intrusions (compromise recording)
• Don’t trust infrastructure
• Don’t trust services
• Establish secure defaults (psychological acceptability)

Authors

HDT