Uncommon Link.EXE Parent Process

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About the rule

Rule Type

Standard

Rule Description

Detects an uncommon parent process of "LINK.EXE". Link.EXE in Microsoft incremental linker. Its a utility usually bundled with Visual Studio installation. Multiple utilities often found in the same folder (editbin.exe, dumpbin.exe, lib.exe, etc) have a hardcode call to the "LINK.EXE" binary without checking its validity. This would allow an attacker to sideload any binary with the name "link.exe" if one of the aforementioned tools get executed from a different location. By filtering the known locations of such utilities we can spot uncommon parent process of LINK.EXE that might be suspicious or malicious.

Severity

Trouble

Rule Requirement

Criteria

Action1: actionname = "Process started" AND (PROCESSNAME endswith "\link.exe" AND COMMANDLINE contains "LINK /") AND (PARENTPROCESSNAME notstartswith "C:\Program Files\Microsoft Visual Studio\,C:\Program Files (x86)\Microsoft Visual Studio" OR PARENTPROCESSNAME notcontains "\VC\bin\,\VC\Tools") select Action1.HOSTNAME,Action1.MESSAGE,Action1.COMMANDLINE,Action1.FILE_NAME,Action1.PROCESSNAME,Action1.USERNAME,Action1.PARENTPROCESSNAME

Detection

Execution Mode

realtime

Log Sources

Windows

Author

Nasreddine Bencherchali (Nextron Systems)