CVE-2011-3300 in Firewall Services Module Software
Summary
by MITRE
Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services module in Cisco Catalyst 6500 series devices, with software 7.0 before 7.0(8.13), 7.1 and 7.2 before 7.2(5.4), 8.0 before 8.0(5.25), 8.1 and 8.2 before 8.2(5.11), 8.3 before 8.3(2.23), 8.4 before 8.4(2.6), and 8.5 before 8.5(1.1) and Cisco Firewall Services Module (aka FWSM) 3.1 before 3.1(21), 3.2 before 3.2(22), 4.0 before 4.0(16), and 4.1 before 4.1(7) allow remote attackers to cause a denial of service (device reload) via crafted SunRPC traffic, aka Bug IDs CSCtq06065 and CSCtq09978.
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Analysis
by VulDB Data Team • 11/23/2021
The vulnerability identified as CVE-2011-3300 represents a critical denial of service flaw affecting Cisco Adaptive Security Appliances and Firewall Services Module devices across multiple software versions. This weakness specifically targets the handling of SunRPC (Sun Remote Procedure Call) traffic within the network security infrastructure, creating a pathway for remote attackers to trigger device reboots. The affected platforms include ASA 5500 series appliances and ASA Services modules in Catalyst 6500 series devices, alongside various FWSM versions, making this a widespread concern for organizations relying on Cisco security appliances for network protection. The vulnerability stems from improper input validation and processing of malformed SunRPC packets that the affected devices cannot handle gracefully, leading to system instability and complete service disruption.
The technical implementation of this vulnerability involves the exploitation of a buffer overflow condition or memory corruption issue within the SunRPC processing components of Cisco's security appliances. When these devices receive specially crafted SunRPC traffic, the malformed packets cause the system to enter an unrecoverable state, ultimately resulting in an automatic device reload or reboot. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which addresses stack-based buffer overflow scenarios. The flaw operates at the network protocol level, requiring minimal privileges to exploit and demonstrating the dangerous potential of protocol-level vulnerabilities in security infrastructure devices. Attackers can leverage this weakness without requiring authentication credentials, making it particularly concerning for environments where such devices are exposed to untrusted network traffic.
The operational impact of CVE-2011-3300 extends beyond simple service interruption, as it can severely compromise network availability and business continuity for organizations relying on affected Cisco appliances. Device reboots can occur without warning, potentially disrupting network services during critical operations and creating window of vulnerability for other attacks. Network administrators may experience significant downtime while investigating and resolving the issue, particularly in environments where multiple affected devices exist. The vulnerability's exploitation can be automated, allowing for rapid deployment of denial of service attacks across multiple targets. According to ATT&CK framework category T1499, this represents a network denial of service technique that specifically targets network infrastructure components, potentially enabling attackers to gain further access to network resources during the service disruption period.
Organizations should prioritize immediate remediation by upgrading to patched software versions that address the SunRPC processing vulnerability. Cisco released patches for all affected software versions, including specific releases for each major version line mentioned in the vulnerability description. Network segmentation and access control measures can provide temporary mitigation by limiting exposure to untrusted network traffic, though these approaches do not eliminate the underlying vulnerability. Monitoring for unusual traffic patterns and device reboots can help detect exploitation attempts, while implementing network intrusion detection systems may provide additional visibility into potential attacks. The vulnerability's classification as a remote attack vector means that organizations should consider their network architecture and implement proper firewall rules to restrict SunRPC traffic to only trusted sources. Regular security assessments and vulnerability management processes should include verification of device software versions to prevent similar issues from affecting the security infrastructure.