CVE-2011-3327 in Quagga
Summary
by MITRE
Heap-based buffer overflow in the ecommunity_ecom2str function in bgp_ecommunity.c in bgpd in Quagga before 0.99.19 allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code by sending a crafted BGP UPDATE message over IPv4.
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Analysis
by VulDB Data Team • 12/23/2024
The vulnerability identified as CVE-2011-3327 represents a critical heap-based buffer overflow affecting the Quagga routing daemon's bgpd component. This flaw exists within the ecommunity_ecom2str function located in bgp_ecommunity.c, specifically in the BGP community string processing functionality. The vulnerability manifests when the daemon processes malformed BGP UPDATE messages containing crafted community attributes, creating a condition where attacker-controlled data can overflow heap memory allocations. This type of vulnerability falls under CWE-121, heap-based buffer overflow, which is classified as a severe memory corruption issue that can lead to arbitrary code execution or system instability.
The technical exploitation of this vulnerability occurs through the manipulation of BGP community attributes in UPDATE messages sent over IPv4 networks. When bgpd receives a specially crafted BGP message with malformed community data, the ecommunity_ecom2str function fails to properly validate input length before copying data to heap-allocated buffers. This improper bounds checking creates an exploitable condition where an attacker can overwrite adjacent memory locations, potentially corrupting heap metadata or executable code. The vulnerability is particularly dangerous because it operates at the network protocol level, allowing remote attackers to trigger the overflow without requiring local access or authentication. The flaw demonstrates characteristics consistent with ATT&CK technique T1203, legitimate credentials, as it can be exploited through standard network communication protocols without requiring elevated privileges.
The operational impact of CVE-2011-3327 extends beyond simple denial of service to potentially enable remote code execution, making it a significant threat to network infrastructure stability. When exploited, the buffer overflow can cause bgpd daemon crashes, leading to routing service disruption that affects entire network segments. In scenarios where the overflow allows code execution, attackers could gain control over routing daemons, potentially enabling traffic redirection, network monitoring, or further exploitation of network infrastructure. The vulnerability affects Quagga versions prior to 0.99.19, indicating that this was a known issue that required patching to maintain security posture. Network administrators operating affected versions face potential exposure to attackers who could leverage this vulnerability to compromise routing integrity and network availability.
Mitigation strategies for CVE-2011-3327 should focus on immediate patch application to Quagga versions 0.99.19 or later, which contain the necessary fixes for the buffer overflow condition. Network administrators should implement BGP message filtering and validation mechanisms to detect and reject malformed community attributes before they reach the bgpd daemon. The implementation of input validation controls, including bounds checking and proper memory management practices, should be enforced in all BGP processing components. Additionally, network segmentation and access control measures can limit the potential impact of exploitation by restricting unauthorized network access to routing daemons. Organizations should also monitor for signs of exploitation attempts through network traffic analysis and implement intrusion detection systems to identify malformed BGP UPDATE messages that could indicate active attacks against this vulnerability. The fix implemented in Quagga 0.99.19 addresses the root cause by adding proper input validation and memory boundary checks to prevent the overflow condition from occurring during community string processing.