YARA · Signature Base (Florian Roth / Nextron)
SIGNATURE_BASE_MAL_DLL_Stealer_Nov23
Detects a DLL that steals authentication credentials - was seen being used by LockBit 3.0 affiliates exploiting CVE-2023-4966
- Author
- X__Junior
- Date
- 2023-11-23
- Modified
- 2023-12-05
- Score / Quality
- 80 / 85
What this rule detects
Detects a DLL that steals authentication credentials - was seen being used by LockBit 3.0 affiliates exploiting CVE-2023-4966
Associated malware family: Lockbit.
Targets: Windows PE.
It defines 1 patterns (0 text, 1 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
rule SIGNATURE_BASE_MAL_DLL_Stealer_Nov23 : CVE_2023_4966 FILE
{
meta:
= "Detects a DLL that steals authentication credentials - was seen being used by LockBit 3.0 affiliates exploiting CVE-2023-4966"
= "X__Junior"
= "9cfed8ec-1d04-53d7-88ef-2576075cfc33"
= "2023-11-23"
= "2023-12-05"
= "https://www.cisa.gov/news-events/cybersecurity-advisories/aa23-325a"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ransom_lockbit_citrixbleed_nov23.yar#L41-L54"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
= "17a27b1759f10d1f6f1f51a11c0efea550e2075c2c394259af4d3f855bbcc994"
= "7d0c46d855973cb2c0636aed9c67cfbe47ca260ab1bc842fef1d532725c26910"
= 80
= 85
= "CVE-2023-4966, FILE"
strings:
$op1 = { C7 45 ?? 4D 69 6E 69 C7 45 ?? 44 75 6D 70 C7 45 ?? 57 72 69 74 C7 45 ?? 65 44 75 6D C7 45 ?? 70 00 27 00 C7 45 ?? 44 00 62 00 C7 45 ?? 67 00 68 00 C7 45 ?? 65 00 6C 00 C7 45 ?? 70 00 2E 00 C7 45 ?? 64 00 6C 00 C7 45 ?? 6C 00 00 00}
condition:
uint16( 0 ) == 0x5a4d and all of them
}
Strings (1 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $op1 | hex | { C7 45 ?? 4D 69 6E 69 C7 45 ?? 44 75 6D 70 C7 45 ?? 57 72 69 74 C7 45 ?? 65 44 75 6D C7 45 ?? 70 00 27 00 C7 45 ?? 44 00 62 00 C7 45 ?? 67 00 68 00 C7 45 ?? 65 … |
Condition
uint16( 0 ) == 0x5a4d and all of themIn plain words (Heuristic)
- The file must start with “MZ” — a Windows executable (PE).
- All patterns in the rule must match.
Test this rule in your browser
Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.
Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 17a27b1759f10d1f6f1f51a11c0efea550e2075c2c394259af4d3f855bbcc994
Licence & attribution
Author: X__Junior
Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a
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: 9cfed8ec-1d04-53d7-88ef-2576075cfc33
Tags:CVE_2023_4966FILE
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