CVE-2013-5122 in Linksys Router
Summary
by MITRE
Cisco Linksys Routers EA2700, EA3500, E4200, EA4500: A bug can cause an unsafe TCP port to open which leads to unauthenticated access
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Analysis
by VulDB Data Team • 05/17/2021
The vulnerability identified as CVE-2013-5122 affects several Cisco Linksys router models including the EA2700, EA3500, E4200, and EA4500 series devices. This security flaw represents a critical weakness in the network infrastructure equipment that can potentially allow unauthorized access to network resources. The vulnerability manifests through an unsafe TCP port opening that creates an entry point for malicious actors without requiring authentication credentials. This issue directly impacts the fundamental security posture of affected routers and can compromise the entire network they protect.
The technical implementation of this vulnerability stems from improper handling of TCP port management within the router firmware. When the affected Cisco Linksys routers initialize their network services, a specific TCP port is opened that should not be accessible from external networks. This port typically serves internal administrative functions or diagnostic purposes but is configured in a manner that allows external connections without proper authentication mechanisms. The flaw likely involves inadequate firewall rule configuration or missing access control lists that should prevent external access to these sensitive ports. According to CWE classification, this vulnerability aligns with CWE-284, which addresses improper access control, and CWE-668, which covers insufficient protection of resources.
The operational impact of CVE-2013-5122 extends beyond simple unauthorized access to potentially enable a wide range of malicious activities. An attacker who successfully exploits this vulnerability can gain access to the router's administrative interface, allowing them to modify network configurations, disable security features, redirect traffic, or establish persistent access points within the network. The unauthenticated nature of the access means that attackers do not require any credentials, making the exploitation process straightforward and significantly increasing the attack surface. This vulnerability can be leveraged as a stepping stone for more extensive network penetration, potentially leading to data breaches, man-in-the-middle attacks, or the establishment of botnet command and control channels. The ATT&CK framework would categorize this as a privilege escalation technique, specifically targeting the network infrastructure to gain elevated access rights.
Mitigation strategies for this vulnerability should include immediate firmware updates from Cisco to address the specific TCP port handling issue. Network administrators should also implement additional protective measures such as configuring proper firewall rules to block external access to the affected ports, conducting regular network scans to identify exposed services, and monitoring for unusual network traffic patterns. The implementation of network segmentation can help limit the potential impact of exploitation by isolating critical network segments from the affected devices. Additionally, organizations should consider implementing intrusion detection systems to monitor for exploitation attempts and establish baseline network behavior to quickly identify deviations that might indicate compromise. Regular vulnerability assessments and security audits should be conducted to ensure that all network infrastructure components maintain proper security configurations and that no similar vulnerabilities exist in the broader network ecosystem.