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feat(rules): detect ReadDirectoryChanges shellcode via callback and APC (#1095) #1143

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feat(rules): detect ReadDirectoryChanges shellcode via callback and APC (#1095) #1143

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31 changes: 31 additions & 0 deletions load-code/shellcode/execute-shellcode-via-readdirectorychanges.yml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,31 @@
rule:
meta:
name: execute shellcode via ReadDirectoryChanges APC
namespace: load-code/shellcode
authors:
- sherkhanz
description: Detects abuse of the ReadDirectoryChanges API completion routine combined with an alertable wait state to execute shellcode.
scopes:
static: function
dynamic: span of calls
att&ck:
- Defense Evasion::Process Injection::Asynchronous Procedure Call [T1055.004]
mbc:
- Defense Evasion::Hijack Execution Flow::Abuse Windows Function Calls [F0015.006]
references:
- https://github.com/mandiant/capa-rules/issues/1095
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@mike-hunhoff mike-hunhoff Mar 19, 2026

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Suggested change
- https://github.com/mandiant/capa-rules/issues/1095

- https://osandamalith.com/2025/09/25/executing-shellcode-with-readdirectorychangess-hidden-callback/
- https://github.com/OsandaMalith/CallbackShellcode/blob/main/ReadDirectoryChanges.c
features:
- and:
- or:
- api: ReadDirectoryChangesW
- api: ReadDirectoryChangesA
- api: ReadDirectoryChangesExW
- api: ReadDirectoryChangesExA
Comment on lines +22 to +25
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@mike-hunhoff mike-hunhoff Mar 19, 2026 •
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Please review the rule documentation to understand how capa handles APIs with A/W variants and update accordingly.

- or:
- api: SleepEx
- api: WaitForSingleObjectEx
- api: WaitForMultipleObjectsEx
- api: MsgWaitForMultipleObjectsEx
- api: SignalObjectAndWait
5 changes: 5 additions & 0 deletions load-code/shellcode/execute-shellcode-via-windows-callback-function.yml
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Expand Up @@ -22,6 +22,7 @@ rule:
- https://osandamalith.com/2021/04/01/executing-shellcode-via-callbacks/
- https://github.com/tlsbollei/Malware-Training/blob/main/Code%20Injection/LdrCallEnclave.cpp
- https://osandamalith.com/2025/10/18/rtlregisterwait-shellcode-execution-poc/
- https://osandamalith.com/2025/09/25/executing-shellcode-with-readdirectorychangess-hidden-callback/
examples:
- 10cd7afd580ee9c222b0a87ff241d306:0x10008BE0
- 268d61837aa248c1d49a973612a129ce:0x1000CEC0
Expand Down Expand Up @@ -82,6 +83,10 @@ rule:
- api: ImmEnumInputContext
- api: LdrCallEnclave
- api: LineDDA
- api: ReadDirectoryChangesA
- api: ReadDirectoryChangesW
- api: ReadDirectoryChangesExA
- api: ReadDirectoryChangesExW
Comment on lines +86 to +89
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@mike-hunhoff mike-hunhoff Mar 19, 2026

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Please review the rule documentation to understand how capa handles APIs with A/W variants and update accordingly.

- and:
- api: RtlRegisterWait
- api: SetEvent
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