CVE-2019-3977 in RouterOS
Summary
by MITRE
RouterOS 6.45.6 Stable, RouterOS 6.44.5 Long-term, and below insufficiently validate where upgrade packages are download from when using the autoupgrade feature. Therefore, a remote attacker can trick the router into "upgrading" to an older version of RouterOS and possibly reseting all the system's usernames and passwords.
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Analysis
by VulDB Data Team • 01/29/2024
The vulnerability identified as CVE-2019-3977 affects MikroTik RouterOS versions 6.45.6 Stable, 6.44.5 Long-term, and earlier releases, specifically targeting the autoupgrade functionality. This flaw represents a critical security weakness in the firmware update mechanism that could enable remote attackers to manipulate the system's upgrade process. The vulnerability stems from insufficient validation of download sources during the automatic upgrade procedure, creating an attack vector that allows malicious actors to influence the firmware installation process.
The technical implementation of this vulnerability involves the autoupgrade feature's failure to properly authenticate or verify the integrity of upgrade packages sourced from remote locations. When a router configured with autoupgrade attempts to fetch firmware updates, the system does not adequately validate the origin or authenticity of the downloaded packages. This validation gap allows attackers to potentially serve malicious upgrade packages through compromised or malicious servers, leading to unauthorized firmware installations. The flaw specifically enables attackers to trick the router into downloading and installing older versions of RouterOS, which may contain known vulnerabilities or backdoors.
The operational impact of this vulnerability extends beyond simple firmware manipulation to include complete system compromise through credential reset capabilities. When the router installs an older firmware version, the process may include resetting all system usernames and passwords, effectively providing attackers with complete administrative control over the network device. This credential reset functionality, combined with the ability to install arbitrary firmware versions, creates a scenario where attackers can gain persistent access to the network infrastructure while potentially establishing a foothold for further attacks. The vulnerability affects network security infrastructure at a fundamental level, as routers serve as critical control points for network operations.
Mitigation strategies for CVE-2019-3977 should prioritize immediate firmware updates to versions that address the authentication and validation issues within the autoupgrade feature. Organizations must also implement network segmentation and access controls to limit exposure of affected devices to untrusted networks. The vulnerability aligns with CWE-22 Improper Limitation of a Pathname to a Restricted Directory and CWE-345 Insufficient Verification of Data Authenticity, both of which relate to inadequate input validation and authentication mechanisms. From an ATT&CK perspective, this vulnerability maps to T1078 Valid Accounts and T1543 Create or Modify System Process, as it enables persistent access through credential manipulation and system-level modifications. Network administrators should disable autoupgrade functionality on affected devices until proper security patches are applied and implement monitoring for unusual firmware update activities to detect potential exploitation attempts.