CVE-2011-3271 in IOS
Summary
by MITRE
Unspecified vulnerability in the Smart Install functionality in Cisco IOS 12.2 and 15.1 allows remote attackers to execute arbitrary code or cause a denial of service (device crash) via crafted TCP packets to port 4786, aka Bug ID CSCto10165.
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Analysis
by VulDB Data Team • 03/19/2021
The vulnerability identified as CVE-2011-3271 represents a critical security flaw within Cisco IOS operating systems affecting versions 12.2 and 15.1. This issue resides within the Smart Install functionality, which is designed to facilitate automated software deployment and configuration management across Cisco network devices. The Smart Install feature enables administrators to remotely provision and update network equipment, streamlining network management processes but inadvertently creating a significant attack surface when improperly secured.
The technical exploitation of this vulnerability occurs through crafted TCP packets transmitted to port 4786, which serves as the designated communication port for the Smart Install protocol. Attackers can manipulate the packet structure to trigger memory corruption or buffer overflow conditions within the IOS processing stack. This flaw allows for two primary attack vectors: remote code execution and denial of service conditions that can result in complete device crashes. The vulnerability demonstrates characteristics consistent with CWE-121, heap-based buffer overflow, where insufficient bounds checking permits attackers to overwrite critical memory regions and potentially execute malicious code with elevated privileges.
The operational impact of this vulnerability extends beyond simple device compromise, as it can affect entire network infrastructures depending on the deployment scope of affected devices. Network administrators who have implemented Smart Install functionality across their enterprise networks face significant risk exposure, as the attack can be executed remotely without requiring authentication credentials. The vulnerability's potential for causing denial of service represents a particularly concerning aspect, as it can disrupt network operations and availability for extended periods while devices undergo restart procedures and recovery processes. This threat aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1498 for network denial of service, demonstrating the multi-faceted nature of the attack surface.
Mitigation strategies for CVE-2011-3271 should prioritize immediate network segmentation and access control measures to limit exposure to untrusted networks. Organizations must disable Smart Install functionality on affected devices when not actively required for network management operations, as this represents the most effective immediate remediation. Network administrators should implement firewall rules to block incoming traffic on port 4786 from unauthorized sources while maintaining proper logging and monitoring capabilities to detect potential exploitation attempts. Cisco released specific patches and software updates addressing this vulnerability, requiring administrators to upgrade to patched IOS versions that include enhanced input validation and memory protection mechanisms. The implementation of these security controls should be prioritized in accordance with the CVSS score and the critical nature of the vulnerability, as unpatched systems remain susceptible to exploitation by threat actors seeking to compromise network infrastructure and establish persistent access points within enterprise environments.