This rule detects the presence of the Kryptonv05 YARA signature, which likely identifies a specific low-severity malware variant or suspicious code pattern within Azure workloads. Proactively hunting for this indicator allows the SOC team to identify early-stage or dormant threats that may not yet trigger high-fidelity alerts, enabling faster containment before the adversary achieves their objectives.
rule Kryptonv05
{
meta:
author="malware-lu"
strings:
$a0 = { 54 E8 [4] 5D 8B C5 81 ED 71 44 [2] 2B 85 64 60 [2] EB 43 DF }
condition:
$a0 at pe.entry_point
}This YARA rule can be deployed in the following contexts:
This rule contains 1 string patterns in its detection logic.
Scenario: A developer or DevOps engineer uses a legitimate binary distribution tool like Chocolatey or Winget to install or update a package that includes a helper script or executable named krypton.exe or similar, which is part of a known software suite (e.g., a crypto utility or a specific vendor’s agent).
choco.exe, winget.exe, or msiexec.exe and the file path resides in standard installation directories like C:\Program Files\ or C:\ProgramData\.Scenario: An IT administrator runs a scheduled PowerShell script via Task Scheduler to perform disk encryption or key management tasks using a custom internal tool or a third-party utility (e.g., BitLocker Management Tool or Veeam Agent) that drops a temporary executable or uses a binary with a name matching the YARA signature.
svchost.exe (specifically the Task Scheduler service) or powershell.exe launched by schtasks.exe, and the working directory is a known admin tool path such as C:\AdminTools\ or C:\Scripts\.Scenario: A security or compliance team runs a vulnerability scanner or configuration audit tool like Nessus, Qualys, or Tenable.io that includes a local agent or helper binary for data collection, which may be signed by a known CA but has a filename or module name that triggers the YARA rule due to generic naming conventions.