Skip to content

T1553.004 Install Root Certificate

Adversaries may install a root certificate on a compromised system to avoid warnings when connecting to adversary controlled web servers. Root certificates are used in public key cryptography to identify a root certificate authority (CA). When a root certificate is installed, the system or application will trust certificates in the root’s chain of trust that have been signed by the root certificate.1 Certificates are commonly used for establishing secure TLS/SSL communications within a web browser. When a user attempts to browse a website that presents a certificate that is not trusted an error message will be displayed to warn the user of the security risk. Depending on the security settings, the browser may not allow the user to establish a connection to the website.

Installation of a root certificate on a compromised system would give an adversary a way to degrade the security of that system. Adversaries have used this technique to avoid security warnings prompting users when compromised systems connect over HTTPS to adversary controlled web servers that spoof legitimate websites in order to collect login credentials.2

Atypical root certificates have also been pre-installed on systems by the manufacturer or in the software supply chain and were used in conjunction with malware/adware to provide Adversary-in-the-Middle capability for intercepting information transmitted over secure TLS/SSL communications.3

Root certificates (and their associated chains) can also be cloned and reinstalled. Cloned certificate chains will carry many of the same metadata characteristics of the source and can be used to sign malicious code that may then bypass signature validation tools (ex: Sysinternals, antivirus, etc.) used to block execution and/or uncover artifacts of Persistence.4

In macOS, the Ay MaMi malware uses /usr/bin/security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /path/to/malicious/cert to install a malicious certificate as a trusted root certificate into the system keychain.5

Item Value
ID T1553.004
Sub-techniques T1553.001, T1553.002, T1553.003, T1553.004, T1553.005, T1553.006
Tactics TA0005
Platforms Linux, Windows, macOS
Permissions required Administrator, User
Version 1.1
Created 21 February 2020
Last Modified 30 March 2023

Procedure Examples

ID Name Description
S0160 certutil certutil can be used to install browser root certificates as a precursor to performing Adversary-in-the-Middle between connections to banking websites. Example command: certutil -addstore -f -user ROOT ProgramData\cert512121.der.9
S0281 Dok Dok installs a root certificate to aid in Adversary-in-the-Middle actions using the command add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain /tmp/filename.1314
S0009 Hikit Hikit uses certmgr.exe -add GlobalSign.cer -c -s -r localMachine Root and certmgr.exe -add GlobalSign.cer -c -s -r localMachineTrustedPublisher to install a self-generated certificate to the local trust store as a root CA and Trusted Publisher.10
S0148 RTM RTM can add a certificate to the Windows store.1112

Mitigations

ID Mitigation Description
M1028 Operating System Configuration Windows Group Policy can be used to manage root certificates and the Flags value of HKLM\SOFTWARE\Policies\Microsoft\SystemCertificates\Root\ProtectedRoots can be set to 1 to prevent non-administrator users from making further root installations into their own HKCU certificate store. 4
M1054 Software Configuration HTTP Public Key Pinning (HPKP) is one method to mitigate potential Adversary-in-the-Middle situations where and adversary uses a mis-issued or fraudulent certificate to intercept encrypted communications by enforcing use of an expected certificate. 8

Detection

ID Data Source Data Component
DS0017 Command Command Execution
DS0009 Process Process Creation
DS0024 Windows Registry Windows Registry Key Creation

References

  1. Wikipedia. (2016, December 6). Root certificate. Retrieved February 20, 2017. ↩

  2. Sancho, D., Hacquebord, F., Link, R. (2014, July 22). Finding Holes Operation Emmental. Retrieved February 9, 2016. ↩

  3. Onuma. (2015, February 24). Superfish: Adware Preinstalled on Lenovo Laptops. Retrieved February 20, 2017. ↩

  4. Graeber, M. (2017, December 22). Code Signing Certificate Cloning Attacks and Defenses. Retrieved April 3, 2018. ↩↩

  5. Patrick Wardle. (2018, January 11). Ay MaMi. Retrieved March 19, 2018. ↩

  6. Russinovich, M. et al.. (2017, May 22). Sigcheck. Retrieved April 3, 2018. ↩

  7. Smith, T. (2016, October 27). AppUNBlocker: Bypassing AppLocker. Retrieved December 19, 2017. ↩

  8. Wikipedia. (2017, February 28). HTTP Public Key Pinning. Retrieved March 31, 2017. ↩

  9. Levene, B., Falcone, R., Grunzweig, J., Lee, B., Olson, R. (2015, August 20). Retefe Banking Trojan Targets Sweden, Switzerland and Japan. Retrieved July 3, 2017. ↩

  10. Glyer, C., Kazanciyan, R. (2012, August 22). The “Hikit” Rootkit: Advanced and Persistent Attack Techniques (Part 2). Retrieved May 4, 2020. ↩

  11. Faou, M. and Boutin, J. (2017, February). Read The Manual: A Guide to the RTM Banking Trojan. Retrieved March 9, 2017. ↩

  12. Duncan, B., Harbison, M. (2019, January 23). Russian Language Malspam Pushing Redaman Banking Malware. Retrieved June 16, 2020. ↩

  13. Patrick Wardle. (n.d.). Mac Malware of 2017. Retrieved September 21, 2018. ↩

  14. fluffybunny. (2019, July 9). OSX.Dok Analysis. Retrieved October 4, 2021. ↩