A critical security flaw has been identified in Motorola MR2600 Wi-Fi routers, allowing attackers on the local network to execute unauthorized code by exploiting the firmware update process. This vulnerability does not require attackers to log in to the router’s administration panel, posing a significant security risk to affected devices.
Details of the Vulnerability
Discovered by security researcher MrBruh, the flaw lies in the firmware upload and validation mechanisms of the Motorola MR2600, with its latest firmware version released in mid-2024. The issue is rooted in the two-step firmware update procedure, where attackers can send a specially crafted request to the router’s firmware upload endpoint.
The router is set to receive firmware images formatted in SEAMA and checks for specific header values during the upload process. However, the validation process incorrectly evaluates the complete HTTP multipart request instead of the actual uploaded file. This misstep allows attackers to bypass security checks by directly submitting the firmware image, exploiting the upload handler’s flawed logic.
Exploitation Process
After receiving the upload, the router performs an authentication check, but this occurs too late—the malicious firmware has already been stored in the temporary directory of the device. The router fails to remove the file if authentication subsequently fails, leaving it available for further exploitation.
The second aspect of the flaw involves the firmware validation via the router’s SOAP endpoint. Although this endpoint is supposed to authenticate requests, it suffers from inconsistent URL matching rules. Attackers can manipulate the URL to access protected firmware functions without proper authorization.
Once authentication is bypassed, attackers can initiate the firmware validation process, which checks the SEAMA structure and CRC32 checksum but does not enforce cryptographic signing. As a result, a crafted malicious firmware image can pass these checks, allowing attackers to run their own code on the router.
Impact and Recommendations
This vulnerability presents a persistent threat, as attackers can modify network configurations, intercept traffic, deploy malware, or use the compromised router as a launchpad for further attacks. The exploit is feasible for unauthenticated attackers within the local network, and potentially over the internet if remote management is enabled.
MrBruh’s findings, corroborated by the internet scanning service Shodan, revealed that some Motorola MR2600 routers are exposed online with remote management active. Despite attempts to report this issue, Motorola has not provided a clear response, as the router model is reportedly at the end of its lifecycle.
To mitigate risks, users should disable remote management on MR2600 routers, limit administrative access to trusted networks, and consider upgrading to newer, supported devices to ensure enhanced security.
