YARA · SEKOIA.IO Community
SEKOIA_Koiloader_Powershell_Reflective_Loading
Powershell script loading service.exe (related to Koi Loader)
- Author
- Sekoia.io
- Date
- 2024-03-20
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
Powershell script loading service.exe (related to Koi Loader)
Associated malware family: Koiloader.
It defines 5 patterns (5 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
koiloader-powershell-reflective-loading.yarDetection Rule License 1.1
rule SEKOIA_Koiloader_Powershell_Reflective_Loading : FILE
{
meta:
= "Powershell script loading service.exe (related to Koi Loader)"
= "Sekoia.io"
= "9bbe4cea-3e64-4377-bf93-def9fb629734"
= "2024-03-20"
= "2024-12-19"
= "https://github.com/SEKOIA-IO/Community"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/koiloader_powershell_reflective_loading.yar#L1-L19"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "27deec01027a73129c6c8057eff1b48190c89ac18dcd7c390fc177d82a897290"
= 75
= 80
= "FILE"
= "1.0"
= "TLP:CLEAR"
strings:
$s1 = "[Byte[]]$image" ascii fullword
$s2 = "function GDT"
$s3 = "function GPA"
$s4 = "GDT @([IntPtr], [UInt32], [IntPtr], [IntPtr], [UInt32], [IntPtr]) ([IntPtr])"
$s5 = "$marshal::GetDelegateForFunctionPointer($CTAddr, $CTDeleg)"
condition:
$s1 at 0 and 4 of them
}
Strings (5 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $s1 | text | "[Byte[]]$image" | ascii fullword |
| $s2 | text | "function GDT" | |
| $s3 | text | "function GPA" | |
| $s4 | text | "GDT @([IntPtr], [UInt32], [IntPtr], [IntPtr], [UInt32], [IntPtr]) ([IntPtr])" | |
| $s5 | text | "$marshal::GetDelegateForFunctionPointer($CTAddr, $CTDeleg)" |
Condition
$s1 at 0 and 4 of themIn plain words (Heuristic)
- At least 4 patterns in the rule must match.
- Pattern $s1 must be found at offset 0.
Test this rule in your browser
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References
Licence & attribution
Author: Sekoia.io
Source repository: SEKOIA.IO Community @ a438a5901a
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: 9bbe4cea-3e64-4377-bf93-def9fb629734
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
Tags:FILE
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