CVE-2011-3278 in IOS
Summary
by MITRE
Unspecified vulnerability in the NAT implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1, and IOS XE 3.1.xSG, allows remote attackers to cause a denial of service (device reload) by sending crafted SIP packets to UDP port 5060, aka Bug ID CSCti48483.
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Analysis
by VulDB Data Team • 11/23/2021
The vulnerability described in CVE-2011-3278 represents a critical flaw in Cisco's network operating system implementations that affects multiple versions of IOS and IOS XE software. This issue specifically targets the Network Address Translation functionality within Cisco's routing and switching platforms, creating a pathway for remote attackers to disrupt network services through carefully constructed Session Initiation Protocol packets. The vulnerability manifests when the system processes malformed SIP traffic directed at the standard UDP port 5060, which is commonly used for VoIP communications and signaling protocols.
The technical nature of this flaw stems from inadequate input validation within the NAT processing module of Cisco IOS. When the system receives crafted SIP packets that exploit specific parsing behaviors in the NAT implementation, it triggers an unexpected state condition that ultimately leads to system instability. This vulnerability operates at the protocol processing layer where SIP traffic is handled, making it particularly dangerous as it can be exploited without requiring authentication or privileged access. The flaw demonstrates a classic buffer over-read or improper state handling issue that has been classified under CWE-129 as an insufficient input validation problem, where the system fails to properly validate the structure and content of incoming network packets before processing them through NAT translation mechanisms.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire network infrastructures that rely on Cisco devices for routing and connectivity. When exploited successfully, the vulnerability forces the affected device to reload its operating system, effectively removing it from service until manual intervention occurs. This creates cascading effects in network environments where multiple Cisco devices may be interconnected, potentially leading to widespread outages and communication failures. The attack vector is particularly concerning because it can be executed remotely over the network without requiring physical access or network credentials, making it a significant threat to enterprise and service provider networks that depend on these devices for core infrastructure functions.
Network administrators and security professionals should implement immediate mitigation strategies including the deployment of access control lists to filter SIP traffic on UDP port 5060, applying Cisco's recommended software patches and updates, and implementing network segmentation to limit exposure. The vulnerability aligns with ATT&CK technique T1498 which covers network denial of service attacks, and represents a sophisticated method of achieving system compromise through protocol manipulation rather than traditional exploit vectors. Organizations should also consider implementing network monitoring solutions that can detect anomalous SIP traffic patterns and establish incident response procedures to address potential exploitation attempts. The affected versions of IOS and IOS XE represent a broad attack surface that requires comprehensive vulnerability management programs to ensure all network infrastructure components receive timely security updates and patches.