hll shellcode

Author: David Zimmer
Date: 06.24.11 - 7:56am

I have been seeing more and more shellcode written in high level languages lately. This last week alone i think I have seen about 5 distinct samples.

The only public hll shellcode templates i have found for Windows are one by didier stevens, and one called WishMaster.

What i am seeing falls into the following catagories:
  • Shellcodized C used in process injection payloads. ThreadStart argument is a prebuilt api table for the payload to use. To analyze these, I had to update the patchgen.exe so that you could also control the initial register state.

  • Shellcode stub that links to a C obj file. In these payloads the asm author has just decided to use certain hll functions such as an encryption library or whatever. Initilization and setup of function pointers and strings seems to still be preferred to be done in the asm stub.

  • single hll function extracts which use advanced or bulky WinApi. Function pointers usually passed in from asm.

  • I have also seen a couple which use variations on didiers template technique.
Shellcode sophistication is also on the rise, having the shellcode do more and more actions on its own. Both of these trends are only going to grow.

Multistage shellcode is also still alive and well, but everything i have seen is file format based. Extracting level 2 shellcode from the parent file and/or extracting exe payloads from the host exploit file.

Comments: (1)

On 07.04.11 - 8:20am Dave wrote:
thanks to Han for submitting another example of a hll shellcode. This one was fully written in C except for the initial decoder. It is based off of the didier template, passing a pointer to the api table into each function and using his or, shl hasher to find LoadLibrary and GetProcAddress. Strings in this sample were embedded differently though using inline asm to call overstring, pop [var_x].

This was a complex sample which mounted a sophisticated attack against AhnLab AV. It made numerous calls to the service control manager to disable services, did registry key checks, and even loads one of their dlls to call exports related to product uninstallation.

Also these attackers look like they are uploading their (encoded) malicious exes as files with image extensions to places like messagesboards or image hosting places so they can get free malware hosting. Thats pretty smart actually...

Thanks again for the interesting submission.

Leave Comment:
Email: (not shown)
Message: (Required)
Math Question: 10 + 28 = ? followed by the letter: J 

About Me
More Blogs
Main Site
Yara WorkBench
vbdec dbg updates
vb6 PCode NOP
vb6 API and call backs
how pcode works Pt1
Reversing PCode Args
VB6 PCode Disassembly
VB6 PCode Debugger
UConnect Disable Cell Modem
IDA python over IPC
dns wildcard blocking
64bit IDA Plugins
anterior lines
misc news/updates
Decoders again
CDO.Message Breakpoints
SysAnalyzer Updates
SysAnalyzer and Site Updates
crazy decoder
ida js w/dbg
flash patching #2
JS Graphing
packet reassembly
Delphi IDA Plugin
scdbg IDA integration
API Hash Database
Winmerge plugin
IDACompare Updates
Guest Post @ hexblog
TCP Stream Reassembly
SysAnalyzer Updates
Apilogger Video
Shellcode2Exe trainer
scdbg updates
IDA Javascript w/IDE
Rop Analysis II
scdbg vrs ROP
flash patching
x64 Hooks
micro hook
jmp api+5 *2
SysAnalyzer Updates
InjDll runtime config
C# Asm/Dsm Library
Shellcode Hook Detection
Updates II
Java Hacking
Windows 8
Win7 x64
Graphing ideas
.Net Hacking
Old iDefense Releases
hll shellcode
ActionScript Tips
-patch fu
scdbg ordinal lookup
scdbg -api mode
Peb Module Lists
scdbg vrs Process Injection
GetProcAddress Scanner
scdbg fopen mode
scdbg findsc mode
scdbg MemMonitor
demo shellcodes
scdbg download
api hashs redux
Api hash gen
Retro XSS Chat Codes
Exe as DLL
Olly Plugins
Debugging Explorer
Attach to hidden process
JS Refactoring
Asm and Shellcode in CSharp
Fancy Return Address
PDF Stream Dumper
Malcode Call API by Hash
WinDbg Cheat Sheet
GPG Automation