YARA · SEKOIA.IO Community
SEKOIA_Guloader_Vbscript
visual basic script delivering GuLoader
- Author
- Sekoia.io
- Date
- 2024-02-07
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
visual basic script delivering GuLoader
It defines 3 patterns (3 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
guloader-vbscript.yarDetection Rule License 1.1
rule SEKOIA_Guloader_Vbscript : FILE
{
meta:
= "visual basic script delivering GuLoader"
= "Sekoia.io"
= "3472e403-b1e6-4fdf-9770-af42d505b556"
= "2024-02-07"
= "2024-12-19"
= "https://github.com/SEKOIA-IO/Community"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/guloader_vbscript.yar#L1-L17"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "d0398b19ec57cff8afd52b06dc9da18788b1eefdf6be70650138e9b342d91d24"
= 75
= 80
= "FILE"
= "1.0"
= "TLP:CLEAR"
strings:
$s1 = " = CreateObject(\"WScript.Shell\")"
$s2 = " = Join("
$s3 = ",vbnullstring)"
condition:
filesize < 20KB and all of them and #s1 > 1 and @s3- @s2 < 16
}
Strings (3 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $s1 | text | " = CreateObject(\"WScript.Shell\")" | |
| $s2 | text | " = Join(" | |
| $s3 | text | ",vbnullstring)" |
Condition
filesize < 20KB and all of them and #s1 > 1 and @s3- @s2 < 16In plain words (Heuristic)
- The file must be smaller than 20KB (a cheap guard that skips large files).
- All patterns in the rule must match.
- Pattern $s1 must occur > 1 times.
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: 3472e403-b1e6-4fdf-9770-af42d505b556
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
Tags:FILE
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