Expand.exe

Binary that expands one or more compressed files

Paths

• C:\Windows\System32\Expand.exe
• C:\Windows\SysWOW64\Expand.exe

Commands

Download

Copies source file to destination.

Use case: Use to copies the source file to the destination file

Privileges: User

expand {PATH_SMB:.bat} {PATH_ABSOLUTE:.bat}

Copy

Copies source file to destination.

Use case: Copies files from A to B

Privileges: User

expand {PATH_ABSOLUTE:.source.ext} {PATH_ABSOLUTE:.dest.ext}

ADS

Copies source file to destination Alternate Data Stream (ADS)

Use case: Copies files from A to B

Privileges: User

expand {PATH_SMB:.bat} {PATH_ABSOLUTE}:file.bat

Detection

• Sigma: https://github.com/SigmaHQ/sigma/blob/c04bef2fbbe8beff6c7620d5d7ea6872dbe7acba/rules/windows/process_creation/proc_creation_win_expand_cabinet_files.yml
• Elastic: https://github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/defense_evasion_misc_lolbin_connecting_to_the_internet.toml

Resources

• https://twitter.com/infosecn1nja/status/986628482858807297
• https://twitter.com/Oddvarmoe/status/986709068759949319