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improve Heaven's Gate detection for computed selector variants #1127

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improve Heaven's Gate detection for computed selector variants #1127

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45 changes: 32 additions & 13 deletions anti-analysis/anti-disasm/64-bit-execution-via-heavens-gate.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -13,21 +13,40 @@ rule:
references:
- https://download.bitdefender.com/resources/files/News/CaseStudies/study/318/Bitdefender-TRR-Whitepaper-Maze-creat4351-en-EN-GenericUse.pdf
- https://www.malwaretech.com/2014/02/the-0x33-segment-selector-heavens-gate.html
- https://github.com/mandiant/capa-rules/issues/1096
examples:
- 79abd17391adc6251ecdc58d13d76baf:0x10002385
features:
- and:
- arch: i386
- or:
- description: set up retf to push 0x33 to CS indicating 64-bit mode
- instruction:
- mnemonic: push
- number: 0x33
- instruction:
- mnemonic: mov
- number: 0x33
- characteristic: call $+5
description: call $+5 pushes the current EIP onto the stack, +5 to jump past call insn bytes
- instruction:
- mnemonic: add = 'add dword ptr[esp], 5' updates the return address to point after retf
- number: 0x5 = length of add + retf insn bytes
- mnemonic: retf = set EIP = [ESP] and CS = [ESP+4]
- and:
- description: set up retf to push 0x33 to CS indicating 64-bit mode
- or:
- instruction:
- mnemonic: push
- number: 0x33
- instruction:
- mnemonic: mov
- number: 0x33
- characteristic: call $+5
description: call $+5 pushes the current EIP onto the stack, +5 to jump past call insn bytes
- instruction:
- mnemonic: add = 'add dword ptr[esp], 5' updates the return address to point after retf
- number: 0x5 = length of add + retf insn bytes
- mnemonic: retf = set EIP = [ESP] and CS = [ESP+4]
- and:
- description: obfuscated variant computes selector 0x33 at runtime then transitions using retf
- instruction:
- mnemonic: push
- number: 0x3
- instruction:
- mnemonic: shl
- number: 0x4
- instruction:
- mnemonic: add
- number: 0x3
- instruction:
- mnemonic: push
- number: 0x0
- mnemonic: retf