Extrac32.exe

Commands

1. ADSUser T1564.004

   Extract data from cab file and hide it in an alternate data stream.

   extrac32 {PATH_ABSOLUTE:.cab} {PATH_ABSOLUTE}:file.exe

   Extracts the source CAB file into an Alternate Data Stream (ADS) of the target file.

   os: Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

   Type: Compression

2. ADSUser T1564.004

   Extract data from cab file and hide it in an alternate data stream.

   extrac32 {PATH_ABSOLUTE:.cab} {PATH_ABSOLUTE}:file.exe

   Extracts the source CAB file on an unc path into an Alternate Data Stream (ADS) of the target file.

   os: Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

   Type: Compression

3. DownloadUser T1105

   Download file from UNC/WEBDav

   extrac32 /Y /C {PATH_SMB} {PATH_ABSOLUTE}

   Copy the source file to the destination file and overwrite it.

   os: Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

4. CopyUser T1105

   Copy file

   extrac32.exe /C {PATH_ABSOLUTE:.source.exe} {PATH_ABSOLUTE:.dest.exe}

   Command for copying file from one folder to another

   os: Windows XP, Windows Vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11

Detection

• Elastic https://github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/defense_evasion_misc_lolbin_connecting_to_the_internet.toml
• Sigma https://github.com/SigmaHQ/sigma/blob/c04bef2fbbe8beff6c7620d5d7ea6872dbe7acba/rules/windows/process_creation/proc_creation_win_lolbin_extrac32.yml
• Sigma https://github.com/SigmaHQ/sigma/blob/c04bef2fbbe8beff6c7620d5d7ea6872dbe7acba/rules/windows/process_creation/proc_creation_win_lolbin_extrac32_ads.yml

Resources

• https://oddvar.moe/2018/04/11/putting-data-in-alternate-data-streams-and-how-to-execute-it-part-2/
• https://gist.github.com/api0cradle/cdd2d0d0ec9abb686f0e89306e277b8f
• https://twitter.com/egre55/status/985994639202283520