LC_LOAD_DYLIB Addition

T1546.006

Sub-technique of T1546 Event Triggered Execution.View on attack.mitre.org

About this technique

Adversaries may establish persistence by executing malicious content triggered by the execution of tainted binaries. Mach-O binaries have a series of headers that are used to perform certain operations when a binary is loaded. The LC_LOAD_DYLIB header in a Mach-O binary tells macOS and OS X which dynamic libraries (dylibs) to load during execution time. These can be added ad-hoc to the compiled binary as long as adjustments are made to the rest of the fields and dependencies. There are tools available to perform these changes.

Adversaries may modify Mach-O binary headers to load and execute malicious dylibs every time the binary is executed. Although any changes will invalidate digital signatures on binaries because the binary is being modified, this can be remediated by simply removing the LC_CODE_SIGNATURE command from the binary so that the signature isn’t checked at load time.

Detection rules0

Rules on DetectionCode tagged with T1546.006.

Sigma0

No Sigma rules are mapped to this technique yet.

Splunk0

No Splunk rules are mapped to this technique yet.

Groups0

None recorded.

Software0

None recorded.

Campaigns0

None recorded.

Procedure examples0

No procedure examples are recorded for this technique.

References2

Malware Persistence on OS X Open source
Patrick Wardle. (2015). Malware Persistence on OS X Yosemite. Retrieved July 10, 2017.
Writing Bad Malware for OSX Open source
Patrick Wardle. (2015). Writing Bad @$$ Malware for OS X. Retrieved July 10, 2017.

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