Authorization Vulnerabilities Discovered in Cox Modems: Security Implications for Users
Recently identified vulnerabilities in Cox modems, since patched, pose serious security risks that could have allowed malicious actors unauthorized access to the devices, potentially enabling them to execute harmful commands. A new report from security researcher Sam Curry reveals that an external attacker could have leveraged these flaws to manipulate modem settings, access sensitive personal data of business customers, and gain privileges akin to those held by ISP support staff.
Curry’s findings surfaced following a responsible disclosure update on March 4, 2024. Within a day, the U.S. broadband provider addressed the authorization bypass issues. Fortunately, there is currently no indication that these vulnerabilities were exploited in real-world scenarios. However, the implications of such access raise significant concerns, particularly regarding the extent of control ISPs have over customer devices. Curry expressed his astonishment at the level of access ISPs maintain behind the scenes, stressing the intricate internal systems built by firms like Xfinity that connect consumer devices to externally exposed APIs.
The vulnerabilities are deeply rooted in the TR-069 protocol, which grants Cox support agents the ability to remotely manage modem settings. Curry’s analysis identified approximately 700 exposed API endpoints that could be weaponized, allowing unauthorized command execution through flawed permission handling. For instance, the "profilesearch" endpoint could enable attackers to search for customer accounts merely using a name, subsequently accessing MAC addresses of connected devices and altering business account settings.
More alarmingly, the analysis indicated that an attacker with the right cryptographic secret could overwrite device settings, including modifying configuration parameters and rebooting the modem. Such a comprehensive level of access could lead to significant security breaches, where attackers could not only change settings but also execute arbitrary commands on compromised devices.
In a hypothetical exploitation scenario, an attacker could have utilized these APIs to search for a Cox customer, acquire full account details, extract Wi-Fi passwords, and potentially seize control of the account. These vulnerabilities may stem from the challenges of managing customer devices like modems and routers, particularly in developing a robust REST API that can effectively communicate with a diverse range of modem models. Curry suggests that better authorization mechanisms could have mitigated these risks by preventing extensive access from a single protocol that interfaces with multiple devices.
Considering the assembly of tactics that could align with these vulnerabilities, relevant techniques from the MITRE ATT&CK framework include initial access through exploitation of external services, privilege escalation through mismanaged API permissions, and persistence via persistent access to customer accounts. These tactics highlight the potential paths an adversary could take to exploit weaknesses in the security architecture of ISPs.
As the understanding of these vulnerabilities unfolds, it serves as a stark reminder for business owners to scrutinize their Internet Service Providers’ security practices and the implications of robust API management in their operations. Cybersecurity remains a pressing priority, and the necessity for heightened vigilance and advanced protective measures cannot be overstated.
