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MediumSigmaHQ Florian Roth (Nextron Systems) +3

File Encoded To Base64 Via Certutil.EXE

Detects the execution of certutil with the "encode" flag to encode a file to base64. This can be abused by threat actors and attackers for data exfiltration

Detection logic

Detection requirements

Platform: ESXi Linux macOS Network Devices Windows
The rule states no platform. This is derived from the ATT&CK technique it maps to.
Log source product: windows
Log source category: process_creation

Known benign triggers

As this is a general purpose rule, legitimate usage of the encode functionality will trigger some false positives. Apply additional filters accordingly

References

Links the source published beside this detection. Reference is the link the source wrote, unmodified. Class is decided by this catalogue from the host and path, not stated by the source. Cited by counts published detections citing the same resource, including this one, and the sources beneath it count the repositories this catalogue ingests, which is not the same as independent research.
Reference	Class	Cited by
learn.microsoft.com/en-us/windows-server/administration/windows-commands/certutil	Product documentation	6
lolbas-project.github.io/lolbas/Binaries/Certutil/	Tool	6from 2 sources
unit42.paloaltonetworks.com/new-babyshark-malware-targets-u-s-national-security-think-tanks/	Threat report	2

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