NK_GOLDBACKDOOR_injected_shellcode
YARA-2025-2089
High
general
Active
Detection for injected shellcode that decodes GOLDBACKDOOR
NK_GOLDBACKDOOR_injected_shellcode.yar
Valid Syntax
rule NK_GOLDBACKDOOR_injected_shellcode
{
meta:
author= "Silas Cutler (silas@Stairwell.com)"
description = "Detection for injected shellcode that decodes GOLDBACKDOOR"
reference = "https://stairwell.com/news/threat-research-the-ink-stained-trail-of-goldbackdoor/"
version = "0.1"
strings:
$dec_routine = { 8A 19 57 8B FA 8B 51 01 83 C1 05 85 D2 74 0E 56 8B C1 8B F2 30 18 40 83 EE 01 75 F8 5E 57 }
$rtlfillmemory_load = {B9 4B 17 CD 5B 55 56 33 ED 55 6A 10 50 E8 86 00 00 00 FF D0}
$ = "StartModule"
$log_file_name = {C7 44 24 3C 25 6C 6F 63 50 8D 44 24 40 C7 44 24 44 61 6C 61 70 50 B9 BD 88 17 75 C7 44 24 4C 70 64 61 74 C7 44 24 50 61 25 5C 6C C7 44 24 54 6F 67 5F 67 C7 44 24 58 6F 6C 64 32 C7 44 24 5C 2E 74 78 74}
$ = { B9 8E 8A DD 8D 8B F0 E8 E9 FB FF FF FF D0 }
condition:
3 of them
}
Rule Metadata
author
Silas Cutler (silas@Stairwell.com)
description
Detection for injected shellcode that decodes GOLDBACKDOOR
reference
https://stairwell.com/news/threat-research-the-ink-stained-trail-of-goldbackdoor/
version
0.1
String Definitions
{"name":"$dec_routine","value":"{ 8A 19 57 8B FA 8B 51 01 83 C1 05 85 D2 74 0E 56 8B C1 8B F2 30 18 40 83 EE 01 75 F8 5E 57 }"}
{"name":"$rtlfillmemory_load","value":"{B9 4B 17 CD 5B 55 56 33 ED 55 6A 10 50 E8 86 00 00 00 FF D0}"}
{"name":"$log_file_name","value":"{C7 44 24 3C 25 6C 6F 63 50 8D 44 24 40 C7 44 24 44 61 6C 61 70 50 B9 BD 88 17 75 C7 44 24 4C 70 64 61 74 C7 44 24 50 61 25 5C 6C C7 44 24 54 6F 67 5F 67 C7 44 24 58 6F 6C 64 32 C7 44 24 5C 2E 74 78 74}"}
Threat Analysis
This YARA rule is designed to detect general threats.
Severity Level: High
The rule uses pattern matching to identify specific byte sequences, strings, or behavioral patterns associated with malicious activity.
Detection Capabilities
- File-based detection for executables and documents
- Memory scanning for running processes
- Network traffic analysis support
Command Line Usage
# Scan a single file yara NK_GOLDBACKDOOR_injected_shellcode.yar /path/to/suspicious/file # Scan a directory recursively yara -r NK_GOLDBACKDOOR_injected_shellcode.yar /path/to/directory/ # Scan with metadata output yara -m NK_GOLDBACKDOOR_injected_shellcode.yar target_file # Scan process memory (Linux) yara NK_GOLDBACKDOOR_injected_shellcode.yar /proc/[pid]/exe
Integration Examples
Python (yara-python)
import yara
rules = yara.compile(filepath='NK_GOLDBACKDOOR_injected_shellcode.yar')
matches = rules.match('/path/to/file')
ClamAV Integration
clamscan --yara-rules=NK_GOLDBACKDOOR_injected_shellcode.yar /path/to/scan
Rule Information
YARA ID
YARA-2025-2089
Repository
Created
August 19, 2025
Last Updated
August 19, 2025
Last Imported
Never
Threat Intelligence
Risk Level
High
Category
general
Detection Confidence
Analysis Pending
False Positive Rate
Not Available
Last Seen in Wild
No Data
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