Obtain Capabilities: Code Signing Certificates
Other sub-techniques of Obtain Capabilities (7)
Adversaries may buy and/or steal code signing certificates that can be used during targeting. Code signing is the process of digitally signing executables and scripts to confirm the software author and guarantee that the code has not been altered or corrupted. Code signing provides a level of authenticity for a program from the developer and a guarantee that the program has not been tampered with.(Citation: Wikipedia Code Signing) Users and/or security tools may trust a signed piece of code more than an unsigned piece of code even if they don't know who issued the certificate or who the author is. Prior to Code Signing, adversaries may purchase or steal code signing certificates for use in operations. The purchase of code signing certificates may be done using a front organization or using information stolen from a previously compromised entity that allows the adversary to validate to a certificate provider as that entity. Adversaries may also steal code signing materials directly from a compromised third-party.
Procedure Examples |
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| Name | Description |
|---|---|
| Wizard Spider |
Wizard Spider has obtained code signing certificates signed by DigiCert, GlobalSign, and COMOOD for malware payloads.(Citation: DFIR Ryuk 2 Hour Speed Run November 2020)(Citation: Mandiant FIN12 Oct 2021) |
| OilRig |
OilRig has obtained stolen code signing certificates to digitally sign malware.(Citation: ClearSky OilRig Jan 2017) |
| BlackTech |
BlackTech has used stolen code-signing certificates for its malicious payloads.(Citation: Symantec Palmerworm Sep 2020) |
| Ember Bear |
Ember Bear has stolen legitimate certificates to sign malicious payloads.(Citation: Palo Alto Unit 42 OutSteel SaintBot February 2022 ) |
| FIN8 |
FIN8 has used an expired open-source X.509 certificate for testing in the OpenSSL repository, to connect to actor-controlled C2 servers.(Citation: Bitdefender Sardonic Aug 2021) |
| MegaCortex |
MegaCortex has used code signing certificates issued to fake companies to bypass security controls.(Citation: IBM MegaCortex) |
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During HomeLand Justice, threat actors used tools with legitimate code signing certificates. (Citation: CISA Iran Albanian Attacks September 2022) |
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APT41 DUST used stolen code signing certificates to sign DUSTTRAP malware and components.(Citation: Google Cloud APT41 2024) |
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During Operation Dream Job, Lazarus Group used code signing certificates issued by Sectigo RSA for some of its malware and tools.(Citation: ESET Lazarus Jun 2020) |
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| Threat Group-3390 |
Threat Group-3390 has obtained stolen valid certificates, including from VMProtect and the Chinese instant messaging application Youdu, for their operations.(Citation: Lunghi Iron Tiger Linux) |
| Kimsuky |
Kimsuky has stolen a valid certificate that is used to sign the malware and the dropper.(Citation: S2W Troll Stealer 2024) |
| Lazarus Group |
Lazarus Group has used code signing certificates issued by Sectigo RSA for some of its malware and tools.(Citation: ESET Lazarus Jun 2020) |
Mitigations |
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| Mitigation | Description |
|---|---|
| Pre-compromise |
Pre-compromise mitigations involve proactive measures and defenses implemented to prevent adversaries from successfully identifying and exploiting weaknesses during the Reconnaissance and Resource Development phases of an attack. These activities focus on reducing an organization's attack surface, identify adversarial preparation efforts, and increase the difficulty for attackers to conduct successful operations. This mitigation can be implemented through the following measures: Limit Information Exposure: - Regularly audit and sanitize publicly available data, including job posts, websites, and social media. - Use tools like OSINT monitoring platforms (e.g., SpiderFoot, Recon-ng) to identify leaked information. Protect Domain and DNS Infrastructure: - Enable DNSSEC and use WHOIS privacy protection. - Monitor for domain hijacking or lookalike domains using services like RiskIQ or DomainTools. External Monitoring: - Use tools like Shodan, Censys to monitor your external attack surface. - Deploy external vulnerability scanners to proactively address weaknesses. Threat Intelligence: - Leverage platforms like MISP, Recorded Future, or Anomali to track adversarial infrastructure, tools, and activity. Content and Email Protections: - Use email security solutions like Proofpoint, Microsoft Defender for Office 365, or Mimecast. - Enforce SPF/DKIM/DMARC policies to protect against email spoofing. Training and Awareness: - Educate employees on identifying phishing attempts, securing their social media, and avoiding information leaks. |
Detection
Consider analyzing code signing certificates for features that may be associated with the adversary and/or their developers, such as the thumbprint, algorithm used, validity period, common name, and certificate authority. Malware repositories can also be used to identify additional samples associated with the adversary and identify patterns an adversary has used in procuring code signing certificates. Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on related follow-on behavior, such as Code Signing or Install Root Certificate.
References
- Breitenbacher, D and Osis, K. (2020, June 17). OPERATION IN(TER)CEPTION: Targeted Attacks Against European Aerospace and Military Companies. Retrieved December 20, 2021.
- Unit 42. (2022, February 25). Spear Phishing Attacks Target Organizations in Ukraine, Payloads Include the Document Stealer OutSteel and the Downloader SaintBot. Retrieved June 9, 2022.
- Wikipedia. (2015, November 10). Code Signing. Retrieved March 31, 2016.
- The DFIR Report. (2020, November 5). Ryuk Speed Run, 2 Hours to Ransom. Retrieved November 6, 2020.
- Shilko, J., et al. (2021, October 7). FIN12: The Prolific Ransomware Intrusion Threat Actor That Has Aggressively Pursued Healthcare Targets. Retrieved June 15, 2023.
- ClearSky Cybersecurity. (2017, January 5). Iranian Threat Agent OilRig Delivers Digitally Signed Malware, Impersonates University of Oxford. Retrieved May 3, 2017.
- Threat Intelligence. (2020, September 29). Palmerworm: Espionage Gang Targets the Media, Finance, and Other Sectors. Retrieved March 25, 2022.
- Budaca, E., et al. (2021, August 25). FIN8 Threat Actor Goes Agile with New Sardonic Backdoor. Retrieved August 9, 2023.
- Del Fierro, C. Kessem, L.. (2020, January 8). From Mega to Giga: Cross-Version Comparison of Top MegaCortex Modifications. Retrieved February 15, 2021.
- CISA. (2022, September 23). AA22-264A Iranian State Actors Conduct Cyber Operations Against the Government of Albania. Retrieved August 6, 2024.
- Mike Stokkel et al. (2024, July 18). APT41 Has Arisen From the DUST. Retrieved September 16, 2024.
- Daniel Lunghi. (2023, March 1). Iron Tiger’s SysUpdate Reappears, Adds Linux Targeting. Retrieved March 20, 2023.
- Jiho Kim & Sebin Lee, S2W. (2024, February 7). Kimsuky disguised as a Korean company signed with a valid certificate to distribute Troll Stealer (English ver.). Retrieved January 17, 2025.
Связанные риски
Каталоги
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