Description
Adversaries may install an older version of the operating system of a network device to weaken security. Older operating system versions on network devices often have weaker encryption ciphers and, in general, fewer/less updated defensive features. (Citation: Cisco Synful Knock Evolution)
On embedded devices, downgrading the version typically only requires replacing the operating system file in storage. With most embedded devices, this can be achieved by downloading a copy of the desired version of the operating system file and reconfiguring the device to boot from that file on next system restart. The adversary could then restart the device to implement the change immediately or they could wait until the next time the system restarts.
Downgrading the system image to an older versions may allow an adversary to evade defenses by enabling behaviors such as Weaken Encryption. Downgrading of a system image can be done on its own, or it can be used in conjunction with Patch System Image.
Platforms
Mitigations (6)
Multi-factor AuthenticationM1032
Use multi-factor authentication for user and privileged accounts. Most embedded network devices support TACACS+ and/or RADIUS. Follow vendor prescribed best practices for hardening access control.(Citation: Cisco IOS Software Integrity Assurance - TACACS)
Code SigningM1045
Many vendors provide digitally signed operating system images to validate the integrity of the software used on their platform. Make use of this feature where possible in order to prevent and/or detect attempts by adversaries to compromise the system image. (Citation: Cisco IOS Software Integrity Assurance - Deploy Signed IOS)
Credential Access ProtectionM1043
Some embedded network devices are capable of storing passwords for local accounts in either plain-text or encrypted formats. Ensure that, where available, local passwords are always encrypted, per vendor recommendations. (Citation: Cisco IOS Software Integrity Assurance - Credentials Management)
Privileged Account ManagementM1026
Restrict administrator accounts to as few individuals as possible, following least privilege principles. Prevent credential overlap across systems of administrator and privileged accounts, particularly between network and non-network platforms, such as servers or endpoints.
Password PoliciesM1027
Refer to NIST guidelines when creating password policies. (Citation: NIST 800-63-3)
Boot IntegrityM1046
Some vendors of embedded network devices provide cryptographic signing to ensure the integrity of operating system images at boot time. Implement where available, following vendor guidelines. (Citation: Cisco IOS Software Integrity Assurance - Secure Boot)
References
Frequently Asked Questions
What is T1601.002 (Downgrade System Image)?
T1601.002 is a MITRE ATT&CK technique named 'Downgrade System Image'. It belongs to the Defense Impairment tactic(s). Adversaries may install an older version of the operating system of a network device to weaken security. Older operating system versions on network devices often have weaker encryption ciphers and, i...
How can T1601.002 be detected?
Detection of T1601.002 (Downgrade System Image) typically involves monitoring system logs, network traffic, and endpoint telemetry. Use SIEM rules, EDR solutions, and behavioral analytics to identify suspicious activity associated with this technique.
What mitigations exist for T1601.002?
There are 6 documented mitigations for T1601.002. Key mitigations include: Multi-factor Authentication, Code Signing, Credential Access Protection, Privileged Account Management, Password Policies.
Which threat groups use T1601.002?
While specific threat group attribution may vary, this technique has been observed in various real-world attacks. Check the MITRE ATT&CK website for the latest threat intelligence.