INCrypter03INinYbyz3e NiFe

Hunt Hypothesis

This YARA rule targets the specific memory footprint of the INCrypter03INinYbyz3e NiFe component, which is often associated with low-severity crypter or packing mechanisms used to obscure malicious payloads. Proactively hunting for this signature allows the SOC team to identify potentially obfuscated executables or in-memory implants that may evade standard behavioral detections, ensuring early visibility into stealthy adversary tooling within Azure Sentinel.

YARA Rule

rule INCrypter03INinYbyz3e_NiFe
{
      meta:
		author="malware-lu"
strings:
		$a0 = { 60 64 A1 30 00 00 00 8B 40 0C 8B 40 0C 8D 58 20 C7 03 00 00 00 00 E8 00 00 00 00 5D 81 ED 4D 16 40 00 8B 9D 0E 17 40 00 64 A1 18 00 00 00 8B 40 30 0F B6 40 02 83 F8 01 75 05 03 DB C1 CB 10 8B 8D 12 17 40 00 8B B5 06 17 40 00 51 81 3E 2E 72 73 72 74 65 8B 85 16 17 40 00 E8 23 00 00 00 8B 85 1A 17 40 00 E8 18 00 00 00 8B 85 1E 17 40 00 E8 0D 00 00 00 8B 85 22 17 40 00 E8 02 00 00 00 EB 18 8B D6 3B 46 0C 72 0A 83 F9 01 74 0B 3B 46 34 72 06 BA 00 00 00 00 C3 58 83 FA 00 75 1A 8B 4E 10 8B 7E 0C 03 BD 02 17 40 00 83 F9 00 74 09 F6 17 31 0F 31 1F 47 E2 F7 59 83 C6 28 49 83 F9 00 75 88 8B 85 0A 17 40 00 89 44 24 1C 61 50 C3 }

condition:
		$a0
}

Deployment Notes

This YARA rule can be deployed in the following contexts:

• Microsoft Defender for Endpoint — Custom indicators / advanced hunting
• Email Gateway — Attachment scanning
• File Share Monitoring — Periodic scanning of shared drives
• YARA CLI — Manual threat hunting on endpoints

This rule contains 1 string patterns in its detection logic.

• Source Rule

False Positive Guidance

• Legacy Java Application Deployment: When deploying or updating legacy Java-based enterprise applications (e.g., older versions of SAP NetWeaver, Oracle EBS, or internal banking systems) that utilize custom class loaders or obfuscated JAR files, the YARA rule may match the specific byte patterns of the encrypted or packed class files.
  • Filter/Exclusion: Exclude files located in specific application directories (e.g., C:\Program Files\SAP\, C:\Oracle\Middleware\) and filter by file extension .class or .jar if the rule targets executable memory or specific file headers.
• Antivirus/EDR Self-Update and Component Loading: During scheduled updates or when the EDR agent loads its proprietary detection engine components (e.g., CrowdStrike Falcon, Microsoft Defender for Endpoint, or Carbon Black), the encrypted or packed driver binaries and rule packs may trigger the signature.
  • Filter/Exclusion: Exclude processes and files owned by known EDR vendors (e.g., CrowdStrike Falcon, MsMpEng.exe, CBEngine.exe) and their associated update directories (e.g., C:\ProgramData\CrowdStrike\, C:\Program Files\Microsoft Security Client\).
• Scheduled Backup and Archive Creation: When enterprise backup solutions (e.g., Veeam, Commvault, or Windows Server Backup) create compressed or encrypted backup archives (.vbk, .cab, .zip), the internal structure of the compressed data blocks can sometimes mimic the byte sequence targeted by the YARA rule, especially if the backup includes encrypted volumes.
  • Filter/Exclusion: Exclude files with backup-specific extensions (.vbk, .bkp, .cab) and exclude processes associated with backup services (e.g., VeeamBackup.exe, commvaultcmd.exe, wbadmin.exe).