YARA · SEKOIA.IO Community
SEKOIA_Backdoor_Lin_Bifrost
Detect the Bifrost backdor based on strings
- Author
- Sekoia.io
- Date
- 2024-03-05
- Modified
- 2024-12-19
- Score / Quality
- 75 / 80
What this rule detects
Detect the Bifrost backdor based on strings
Targets: Linux ELF.
It defines 2 patterns (2 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
backdoor-lin-bifrost.yarDetection Rule License 1.1
rule SEKOIA_Backdoor_Lin_Bifrost : FILE
{
meta:
= "Detect the Bifrost backdor based on strings"
= "Sekoia.io"
= "9726b5f5-8cc3-4fad-950b-f20cac04d496"
= "2024-03-05"
= "2024-12-19"
= "https://unit42.paloaltonetworks.com/new-linux-variant-bifrost-malware/"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/backdoor_lin_bifrost.yar#L1-L20"
= "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
= "8e85cb6f2215999dc6823ea3982ff4376c2cbea53286e95ed00250a4a2fe4729"
= "2aeb70f72e87a1957e3bc478e1982fe608429cad4580737abe58f6d78a626c05"
= "f2bef6bed27f4b527118dd62b4035003c14afaffa72729c8117f213623f644ec"
= "a3fd671c02c29f67cf5b8d2d0e857336da72f989688f2db19cd028398080c5e2"
= 75
= 80
= "FILE"
= "1.0"
= "TLP:CLEAR"
strings:
$ = "%c2%s%c3%u%c4%u-%.2u-%.2u %.2u:%.2u"
$ = "%c1%s%c3D%c4%u-%.2u-%.2u %.2u:%.2u"
condition:
uint32be( 0 ) == 0x7f454c46 and all of them
}
Strings (2 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $ | text | "%c2%s%c3%u%c4%u-%.2u-%.2u %.2u:%.2u" | |
| $ | text | "%c1%s%c3D%c4%u-%.2u-%.2u %.2u:%.2u" |
Condition
uint32be( 0 ) == 0x7f454c46 and all of themIn plain words (Heuristic)
- The file must start with the ELF header — a Linux/Unix executable.
- All patterns in the rule must match.
Test this rule in your browser
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Sample hashes
Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).
- 8e85cb6f2215999dc6823ea3982ff4376c2cbea53286e95ed00250a4a2fe4729
- 2aeb70f72e87a1957e3bc478e1982fe608429cad4580737abe58f6d78a626c05
- f2bef6bed27f4b527118dd62b4035003c14afaffa72729c8117f213623f644ec
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: 9726b5f5-8cc3-4fad-950b-f20cac04d496
Metadata
| version | 1.0 |
|---|---|
| classification | TLP:CLEAR |
Tags:FILE
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