Awesome
Dshell
An extensible network forensic analysis framework. Enables rapid development of plugins to support the dissection of network packet captures.
Key features:
- Deep packet analysis using specialized plugins
- Robust stream reassembly
- IPv4 and IPv6 support
- Multiple user-selectable output formats and the ability to create custom output handlers
- Chainable plugins
- Parallel processing option to divide the handling of data source into separate Python processes
- Enables development of external plugin packs to share and install new externally developed plugins without overlapping the core Dshell plugin directories
Guides
- Dshell User Guide
- A guide to installation as well as both basic and advanced analysis with examples
- Helps new and experienced end users with using and understanding the decoder-shell (Dshell) framework
- Dshell Developer Guide
- A guide to plugin development with basic examples, as well as core function and class definitions, and an overview of data flow
- Helps end users develop new, custom Dshell plugins as well as modify existing plugins
Requirements
- Linux (developed on Ubuntu 20.04 LTS)
- Python 3 (developed with Python 3.8.10)
- pypacker
- pcapy-ng
- pyOpenSSL
- geoip2
- MaxMind GeoIP2 data sets
- Used to map IP addresses to country codes
- See Installation section for configuration
- MaxMind GeoIP2 data sets
Optional
- oui.txt
- used by some plugins that handle MAC addresses
- place in <dshell>/data/
- elasticsearch
- used in the elasticout output module
- only necessary if planning to use elasticsearch to store output
- pyJA3
- used in the tls plugin
Installation
- Install Dshell with pip
python3 -m pip install Dshell/ORpython3 -m pip install <Dshell-tarball>
- Configure geoip2 by placing the MaxMind GeoLite2 data set files (GeoLite2-ASN.mmdb, GeoLite2-City.mmdb, GeoLite2-Country.mmdb) in [...]/site-packages/dshell/data/GeoIP/
- Run
dshell. This should drop you into aDshell>prompt.
Basic Usage
decode -l- This will list all available plugins, alongside basic information about them
decode -h- Show generic command-line flags available to most plugins, such as the color blind friendly mode for all color output
decode -p <plugin>- Display information about a plugin, including available command line flags
decode -p <plugin> <pcap>- Run the selected plugin on a pcap or pcapng file
decode -p <plugin1>+<plugin2> <pcap>- Chain two (or more) plugins together and run them on a pcap file
decode -p <plugin> -i <interface>- Run the selected plugin live on an interface (may require superuser privileges)
Usage Examples
Showing DNS lookups in sample traffic
Dshell> decode -p dns ~/pcap/dns.cap | sort
[DNS] 2005-03-30 03:47:46 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 4146, TXT? google.com., TXT: b'\x0fv=spf1 ptr ?all' **
[DNS] 2005-03-30 03:47:50 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 63343, MX? google.com., MX: b'\x00(\x05smtp4\xc0\x0c', MX: b'\x00\n\x05smtp5\xc0\x0c', MX: b'\x00\n\x05smtp6\xc0\x0c', MX: b'\x00\n\x05smtp1\xc0\x0c', MX: b'\x00\n\x05smtp2\xc0\x0c', MX: b'\x00(\x05smtp3\xc0\x0c' **
[DNS] 2005-03-30 03:47:59 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 18849, LOC? google.com. **
[DNS] 2005-03-30 03:48:07 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 39867, PTR? 104.9.192.66.in-addr.arpa., PTR: 66-192-9-104.gen.twtelecom.net. **
[DNS] 2005-03-30 03:49:18 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 30144, A? www.netbsd.org., A: 204.152.190.12 (ttl 82159s) **
[DNS] 2005-03-30 03:49:35 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 61652, AAAA? www.netbsd.org., AAAA: 2001:4f8:4:7:2e0:81ff:fe52:9a6b (ttl 86400s) **
[DNS] 2005-03-30 03:50:35 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 32569, AAAA? www.netbsd.org., AAAA: 2001:4f8:4:7:2e0:81ff:fe52:9a6b (ttl 86340s) **
[DNS] 2005-03-30 03:50:44 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 36275, AAAA? www.google.com., CNAME: 'www.l.google.com.' **
[DNS] 2005-03-30 03:50:54 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 56482, AAAA? www.l.google.com. **
[DNS] 2005-03-30 03:51:35 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 48159, AAAA? www.example.com. **
[DNS] 2005-03-30 03:51:46 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 9837, AAAA? www.example.notginh., NXDOMAIN **
[DNS] 2005-03-30 03:52:17 192.168.170.8:32795 -- 192.168.170.20:53 ** ID: 65251, AAAA: 2001:4f8:0:2::d (ttl 600s), A: 204.152.184.88 (ttl 600s) **
[DNS] 2005-03-30 03:52:17 192.168.170.8:32796 -- 192.168.170.20:53 ** ID: 23123, PTR? 1.0.0.127.in-addr.arpa., PTR: localhost. **
[DNS] 2005-03-30 03:52:17 192.168.170.8:32797 -- 192.168.170.20:53 ** ID: 8330, NS: b'\x06ns-ext\x04nrt1\xc0\x0c', NS: b'\x06ns-ext\x04sth1\xc0\x0c', NS: b'\x06ns-ext\xc0\x0c', NS: b'\x06ns-ext\x04lga1\xc0\x0c' **
[DNS] 2005-03-30 03:52:17 192.168.170.56:1707 -- 217.13.4.24:53 ** ID: 12910, SRV? _ldap._tcp.Default-First-Site-Name._sites.dc._msdcs.utelsystems.local., NXDOMAIN **
[DNS] 2005-03-30 03:52:17 192.168.170.56:1708 -- 217.13.4.24:53 ** ID: 61793, SRV? _ldap._tcp.dc._msdcs.utelsystems.local., NXDOMAIN **
[DNS] 2005-03-30 03:52:17 192.168.170.56:1709 -- 217.13.4.24:53 ** ID: 33633, SRV? _ldap._tcp.05b5292b-34b8-4fb7-85a3-8beef5fd2069.domains._msdcs.utelsystems.local., NXDOMAIN **
[DNS] 2005-03-30 03:52:17 192.168.170.56:1710 -- 217.13.4.24:53 ** ID: 53344, A? GRIMM.utelsystems.local., NXDOMAIN **
[DNS] 2005-03-30 03:52:25 192.168.170.56:1711 -- 217.13.4.24:53 ** ID: 30307, A? GRIMM.utelsystems.local., NXDOMAIN **
Following and reassembling a stream in sample traffic
Dshell> decode -p followstream ~/pcap/v6-http.cap
Connection 1 (TCP)
Start: 2007-08-05 15:16:44.189851
End: 2007-08-05 15:16:44.219460
2001:6f8:102d:0:2d0:9ff:fee3:e8de: 59201 -> 2001:6f8:900:7c0::2: 80 (300 bytes)
2001:6f8:900:7c0::2: 80 -> 2001:6f8:102d:0:2d0:9ff:fee3:e8de: 59201 (2379 bytes)
GET / HTTP/1.0
Host: cl-1985.ham-01.de.sixxs.net
Accept: text/html, text/plain, text/css, text/sgml, */*;q=0.01
Accept-Encoding: gzip, bzip2
Accept-Language: en
User-Agent: Lynx/2.8.6rel.2 libwww-FM/2.14 SSL-MM/1.4.1 OpenSSL/0.9.8b
HTTP/1.1 200 OK
Date: Sun, 05 Aug 2007 19:16:44 GMT
Server: Apache
Content-Length: 2121
Connection: close
Content-Type: text/html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
<html>
<head>
<title>Index of /</title>
</head>
<body>
<h1>Index of /</h1>
<pre><img src="/icons/blank.gif" alt="Icon "> <a href="?C=N;O=D">Name</a> <a href="?C=M;O=A">Last modified</a> <a href="?C=S;O=A">Size</a> <a href="?C=D;O=A">Description</a><hr><img src="/icons/folder.gif" alt="[DIR]"> <a href="202-vorbereitung/">202-vorbereitung/</a> 06-Jul-2007 14:31 -
<img src="/icons/layout.gif" alt="[ ]"> <a href="Efficient_Video_on_demand_over_Multicast.pdf">Efficient_Video_on_d..></a> 19-Dec-2006 03:17 291K
<img src="/icons/unknown.gif" alt="[ ]"> <a href="Welcome%20Stranger!!!">Welcome Stranger!!!</a> 28-Dec-2006 03:46 0
<img src="/icons/text.gif" alt="[TXT]"> <a href="barschel.htm">barschel.htm</a> 31-Jul-2007 02:21 44K
<img src="/icons/folder.gif" alt="[DIR]"> <a href="bnd/">bnd/</a> 30-Dec-2006 08:59 -
<img src="/icons/folder.gif" alt="[DIR]"> <a href="cia/">cia/</a> 28-Jun-2007 00:04 -
<img src="/icons/layout.gif" alt="[ ]"> <a href="cisco_ccna_640-801_command_reference_guide.pdf">cisco_ccna_640-801_c..></a> 28-Dec-2006 03:48 236K
<img src="/icons/folder.gif" alt="[DIR]"> <a href="doc/">doc/</a> 19-Sep-2006 01:43 -
<img src="/icons/folder.gif" alt="[DIR]"> <a href="freenetproto/">freenetproto/</a> 06-Dec-2006 09:00 -
<img src="/icons/folder.gif" alt="[DIR]"> <a href="korrupt/">korrupt/</a> 03-Jul-2007 11:57 -
<img src="/icons/folder.gif" alt="[DIR]"> <a href="mp3_technosets/">mp3_technosets/</a> 04-Jul-2007 08:56 -
<img src="/icons/text.gif" alt="[TXT]"> <a href="neues_von_rainald_goetz.htm">neues_von_rainald_go..></a> 21-Mar-2007 23:27 31K
<img src="/icons/text.gif" alt="[TXT]"> <a href="neues_von_rainald_goetz0.htm">neues_von_rainald_go..></a> 21-Mar-2007 23:29 36K
<img src="/icons/layout.gif" alt="[ ]"> <a href="pruef.pdf">pruef.pdf</a> 28-Dec-2006 07:48 88K
<hr></pre>
</body></html>
Chaining plugins to view flow data for a specific country code in sample traffic (note: TCP handshakes are not included in the packet count)
Dshell> decode -p country+netflow --country_code=JP ~/pcap/SkypeIRC.cap
2006-08-25 15:32:20.766761 192.168.1.2 -> 202.232.205.123 (-- -> JP) UDP 60583 33438 1 0 64 0 0.0000s
2006-08-25 15:32:20.634046 192.168.1.2 -> 202.232.205.123 (-- -> JP) UDP 60583 33435 1 0 64 0 0.0000s
2006-08-25 15:32:20.747503 192.168.1.2 -> 202.232.205.123 (-- -> JP) UDP 60583 33437 1 0 64 0 0.0000s
2006-08-25 15:32:20.651501 192.168.1.2 -> 202.232.205.123 (-- -> JP) UDP 60583 33436 1 0 64 0 0.0000s
Collecting DNS traffic from several files and storing it in a new pcap file.
Dshell> decode -p dns+pcapwriter --pcapwriter_outfile=test.pcap ~/pcap/*.cap > /dev/null
Dshell> tcpdump -nnr test.pcap | head
reading from file test.pcap, link-type EN10MB (Ethernet)
15:36:08.670569 IP 192.168.1.2.2131 > 192.168.1.1.53: 40209+ A? ui.skype.com. (30)
15:36:08.670687 IP 192.168.1.2.2131 > 192.168.1.1.53: 40210+ AAAA? ui.skype.com. (30)
15:36:08.674022 IP 192.168.1.1.53 > 192.168.1.2.2131: 40209- 1/0/0 A 212.72.49.131 (46)
15:36:09.011208 IP 192.168.1.1.53 > 192.168.1.2.2131: 40210 0/1/0 (94)
15:36:10.171350 IP 192.168.1.2.2131 > 192.168.1.1.53: 40210+ AAAA? ui.skype.com. (30)
15:36:10.961350 IP 192.168.1.1.53 > 192.168.1.2.2131: 40210* 0/1/0 (85)
15:36:10.961608 IP 192.168.1.2.2131 > 192.168.1.1.53: 40211+ AAAA? ui.skype.com. (30)
15:36:11.294333 IP 192.168.1.1.53 > 192.168.1.2.2131: 40211 0/1/0 (94)
15:32:21.664798 IP 192.168.1.2.2130 > 192.168.1.1.53: 39862+ A? ui.skype.com. (30)
15:32:21.664913 IP 192.168.1.2.2130 > 192.168.1.1.53: 39863+ AAAA? ui.skype.com. (30)
Collecting TFTP data and converting alerts to JSON format using sample traffic
Dshell> decode -p tftp -O jsonout ~/pcap/tftp_*.pcap
{"ts": 1367411051.972852, "sip": "192.168.0.253", "sport": 50618, "dip": "192.168.0.10", "dport": 3445, "readwrite": "read", "filename": "rfc1350.txt", "plugin": "tftp", "pcapfile": "/home/pcap/tftp_rrq.pcap", "data": "read rfc1350.txt (24599 bytes) "}
{"ts": 1367053679.45274, "sip": "192.168.0.1", "sport": 57509, "dip": "192.168.0.13", "dport": 2087, "readwrite": "write", "filename": "rfc1350.txt", "plugin": "tftp", "pcapfile": "/home/pcap/tftp_wrq.pcap", "data": "write rfc1350.txt (24599 bytes) "}
Running a plugin within a separate Python script using sample traffic
# Import required Dshell libraries
import dshell.decode as decode
import dshell.plugins.tftp.tftp as tftp
# Instantiate plugin
plugin = tftp.DshellPlugin()
# Define plugin-specific arguments, if needed
dargs = {plugin: {"rip": True, "outdir": "/tmp/"}}
# Add plugin(s) to plugin chain
decode.plugin_chain = [plugin]
# Run decode main function with all other arguments
decode.main(
debug=True,
files=["/home/user/pcap/tftp_rrq.pcap", "/home/user/pcap/tftp_wrq.pcap"],
plugin_args=dargs
)