YARA · CAPE Sandbox (CAPEv2)
CAPE_Formhooka
Formbook Anti-hook Bypass
- Author
- kevoreilly
- Date
- 2021-03-07
- Modified
- 2026-05-15
- Score / Quality
- 75 / 70
What this rule detects
Formbook Anti-hook Bypass
Associated malware family: Formbook.
It defines 2 patterns (0 text, 2 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
formhooka.yarGNU General Public License v3.0
rule CAPE_Formhooka
{
meta:
= "Formbook Anti-hook Bypass"
= "kevoreilly"
= "6369de74-99eb-57ae-a315-c15f22effc73"
= "2021-03-07"
= "2026-05-15"
= "https://github.com/kevoreilly/CAPEv2"
= "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/analyzer/windows/data/yara/Formbook.yar#L1-L14"
= "https://github.com/kevoreilly/CAPEv2/blob/6b15e76f28cd83fd1187da6c9aaaad2174255356/LICENSE"
= "21b8101a7039cfad0e9d49cc1f055bc23a2eb4c973dcda2a81a007e452d77a6d"
= 75
= 70
= ""
= "clear,bp0=$remap_ntdll_0,action0=setedx:ntdll,count0=1,bp1=$remap_ntdll_1,action1=setdst:ntdll,count1=1"
= "9e38c0c3c516583da526016c4c6a671c53333d3d156562717db79eac63587522"
= "b8e44f4a0d92297c5bb5b217c121f0d032850b38749044face2b0014e789adfb"
strings:
$remap_ntdll_0 = {33 56 04 8D 86 [2] 00 00 68 F0 00 00 00 50 89 56 ?? E8 [4] 8B [1-5] 6A 00 6A 04 8D 4D ?? 51 6A 07 52 56 E8 [4] 8B 45 ?? 83 C4 20 3B}
$remap_ntdll_1 = {33 56 0C 8D 86 [2] 00 00 68 F0 00 00 00 50 89 56 ?? E8 [4] 8B [1-5] 6A 00 6A 04 8D 4D ?? 51 6A 07 52 56 E8 [4] 8B 45 ?? 83 C4 20 3B}
condition:
any of them
}
Strings (2 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $remap_ntdll_0 | hex | {33 56 04 8D 86 [2] 00 00 68 F0 00 00 00 50 89 56 ?? E8 [4] 8B [1-5] 6A 00 6A 04 8D 4D ?? 51 6A 07 52 56 E8 [4] 8B 45 ?? 83 C4 20 3B} | |
| $remap_ntdll_1 | hex | {33 56 0C 8D 86 [2] 00 00 68 F0 00 00 00 50 89 56 ?? E8 [4] 8B [1-5] 6A 00 6A 04 8D 4D ?? 51 6A 07 52 56 E8 [4] 8B 45 ?? 83 C4 20 3B} |
Condition
any of themIn plain words (Heuristic)
- At least one pattern in the rule must match.
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References
Licence & attribution
Author: kevoreilly
Source repository: CAPE Sandbox (CAPEv2) @ 6b15e76f28
Licence: GNU General Public License v3.0 (repository licence)
Copyright notice: Cuckoo Sandbox is copyrighted by the Cuckoo Foundation.
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 6369de74-99eb-57ae-a315-c15f22effc73
Metadata
| cape_options | clear,bp0=$remap_ntdll_0,action0=setedx:ntdll,count0=1,bp1=$remap_ntdll_1,action1=setdst:ntdll,count1=1 |
|---|---|
| packed | 9e38c0c3c516583da526016c4c6a671c53333d3d156562717db79eac63587522 |
| packed | b8e44f4a0d92297c5bb5b217c121f0d032850b38749044face2b0014e789adfb |
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