expand.exe

by Microsoft
Operating SystemLOLBin

Sources: 300M+ executions observed in the wild.

Summary

Expand (expand.exe) extracts files from compressed Windows cabinet (.cab) files. Used during software installation and Windows component servicing.

expand.exe is the 516th most commonly executed Windows program in EchoTrail's dataset, observed 10,951 times across enterprise environments. It typically runs from C:\Windows\System32 and it is most often launched by ServiceShell.exe.

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516th
most commonly executed Windows program
10,951
observed endpoint executions

Behavior

Top Paths

  • C:\Windows\System3268.18%
  • C:\Windows\SysWOW6431.81%
  • C:\...0.01%

Top Hashes (SHA256)

  • 210a43646b58a60035cedc30281f3414dd6a551a62255aac7ef828c5d7ea46ce23.75%
  • 71d931442aa51e3fecb3c014d189e9125e210507ba8acf8abe83e5c9f6810fe217.73%
  • e4cdd94f52c17d6877851c81e064ea4b85bd247fdb14bff13fdfe16797083c7b17.24%
  • f9e6fc6f310f6f8fa5d2aa1ce9f04391af184382b27b33171d8afd83f55df5ff8.71%
  • 72cedaef15d65f2a88a19f1fff3e420a978b93b0e5bb9fd160fb26b7b9aca8cc8.6%
  • dfc1709a2988301f7a9d145fb107793e3299ecc85f4b9702523939e35573ab856.81%
  • fac091fdd81d75056cb923a6781e6ccf70693ed7a45cc260ad8b6f29c41d7a713.61%
  • 863ef862cc46270ab24508794d578a2f1c08a9a62d889d3ad07e47b525a639a12.57%
  • 8cbff6bc4fd477bfc6647f3aa794241df791480bec0c00866b707c15bf8546ff2.55%
  • 39ec40864c475ee1634b2aedf37e0e7d2a9e27cbd1e3a6c9e357537c491659612.29%

Process Ancestry

Top Grandparents

Top Parents

Top Children

Security Analysis

What does expand.exe normally do?

Located in C:\Windows\System32 or C:\Windows\SysWOW64. Launched by installers (ServiceShell.exe, Lenovo tools) and powershell.exe.

When is expand.exe suspicious?

Extracting files to unusual directories. Extracting DLLs or executables from cab files in temp directories. Launched by unusual parents.

How do attackers abuse expand.exe?

Payload extraction: expand.exe can extract payloads from cab archives, bypassing some file type controls. Listed on LOLBAS as a binary that can be used to extract files for proxy execution.

Detection guidance

Low priority. Monitor for expand.exe extracting executables or DLLs to temp or user profile directories.

False positive notes

Common during software installation and Windows servicing.

MITRE ATT&CK techniques

Related Processes

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