The detection identifies potential execution of the Gh0stMiancha Trojan, which may indicate unauthorized persistence or data exfiltration. SOC teams should proactively hunt for this behavior in Azure Sentinel to detect and mitigate early-stage malware activity that could evade traditional detection methods.
YARA Rule
rule Trojan_W32_Gh0stMiancha_1_0_0
{
meta:
Author = "Context Threat Intelligence"
Date = "2014/01/27"
Description = "Bytes inside"
Reference = "http://www.contextis.com/documents/30/TA10009_20140127_-_CTI_Threat_Advisory_-_The_Monju_Incident1.pdf"
strings:
$0x = { 57 5b 5a 5a 51 57 40 34 31 67 2e 31 70 34 5c 40 40 44 3b 25 3a 19 1e 5c 7b 67 60 2e 34 31 67 2e 31 70 19 1e 55 77 77 71 64 60 2e 34 3e 3b 3e 19 1e 57 7b 7a 60 71 7a 60 39 40 6d 64 71 2e 34 60 71 6c 60 3b 7c 60 79 78 19 1e 44 66 7b 6c 6d 39 57 7b 7a 7a 71 77 60 7d 7b 7a 2e 34 5f 71 71 64 39 55 78 7d 62 71 19 1e 57 7b 7a 60 71 7a 60 39 78 71 7a 73 60 7c 2e 34 24 19 1e 19 1e }
$1 = { 5c e7 99 bd e5 8a a0 e9 bb 91 5c }
$1x = { 48 f3 8d a9 f1 9e b4 fd af 85 48 }
$2 = "DllCanLoadNow"
$2x = { 50 78 78 57 75 7a 58 7b 75 70 5a 7b 63 }
$3x = { 5a 61 79 76 71 66 34 7b 72 34 67 61 76 7f 71 6d 67 2e 34 31 70 }
$4 = "JXNcc2hlbGxcb3Blblxjb21tYW5k"
$4x = { 5e 4c 5a 77 77 26 7c 78 76 53 6c 77 76 27 56 78 76 78 6c 7e 76 26 25 60 4d 43 21 7f }
$5 = "SEFSRFdBUkVcREVTQ1JJUFRJT05cU3lzdGVtXENlbnRyYWxQcm9jZXNzb3JcMA=="
$5x = { 47 51 52 47 46 52 70 56 41 7f 42 77 46 51 42 40 45 25 5e 5e 41 52 46 5e 40 24 21 77 41 27 78 6e 70 53 42 60 4c 51 5a 78 76 7a 46 6d 4d 43 6c 45 77 79 2d 7e 4e 4c 5a 6e 76 27 5e 77 59 55 29 29 }
$6 = "C:\\Users\\why\\"
$6x = { 57 2e 48 41 67 71 66 67 48 63 7c 6d 48 }
$7 = "g:\\ykcx\\"
$7x = { 73 2E 48 6D 7F 77 6C 48 }
$8 = "(miansha)"
$8x = { 3C 79 7D 75 7A 67 7C 75 3D }
$9 = "server(\xE5\xA3\xB3)"
$9x = { 7C 2E 48 26 24 25 27 3A 25 25 3A 26 21 48 67 71 66 62 71 66 3C F1 B7 A7 3D 48 46 71 78 71 75 67 71 48 67 71 66 62 71 66 3A 64 70 76 }
$cfgDecode = { 8a ?? ?? 80 c2 7a 80 f2 19 88 ?? ?? 41 3b ce 7c ??}
condition:
any of them
}This YARA rule can be deployed in the following contexts:
This rule contains 19 string patterns in its detection logic.
Scenario: A system administrator is using PowerShell to automate the deployment of a legitimate software update.
Filter/Exclusion: Exclude processes where the command line contains powershell.exe and the script path includes C:\Windows\System32\WindowsPowerShell\v1.0\ or contains known update deployment tools like WSUS or GroupPolicy.
Scenario: A scheduled job runs Task Scheduler to perform routine system maintenance, such as disk cleanup or log rotation.
Filter/Exclusion: Exclude tasks associated with the Task Scheduler service, specifically those with names containing Cleanup, LogRotate, or DiskDefrag, and where the user is a Local System or Administrators account.
Scenario: A security tool like Microsoft Defender ATP or CrowdStrike is performing a sandboxed analysis or threat emulation.
Filter/Exclusion: Exclude processes where the parent process is a known security tool (e.g., MsMpEng.exe, CrowdStrikeAgent.exe) or where the process is running in a sandboxed environment (e.g., sandboxed.exe, vmtoolsd.exe).
Scenario: A developer is using Visual Studio or Git Bash to run a legitimate script that mimics malicious behavior for testing purposes.
Filter/Exclusion: Exclude processes where the executable is devenv.exe, git.exe, or bash.exe, and where the script path includes known development directories like C:\Users\Dev\Scripts\ or C:\Program Files\Git\.
Scenario: A backup job using Veeam or Acronis is executing a script that temporarily creates suspicious-looking files during the backup process.
Filter/Exclusion: Exclude processes where the parent process is veeam.exe or