CVE-2017-13043 in macOS
Summary
by MITRE
The BGP parser in tcpdump before 4.9.2 has a buffer over-read in print-bgp.c:decode_multicast_vpn().
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2017-13043 represents a critical buffer over-read flaw within the Border Gateway Protocol (BGP) parser component of tcpdump network analysis tool. This issue specifically affects versions prior to 4.9.2 and resides in the print-bgp.c source file at the decode_multicast_vpn() function. The flaw occurs when tcpdump processes BGP packets containing multicast VPN information, creating a scenario where the parser reads beyond the allocated buffer boundaries. Such buffer over-read conditions are particularly dangerous in network monitoring tools like tcpdump since they can lead to unpredictable behavior, system crashes, or potentially exploitable conditions that adversaries might leverage.
The technical implementation of this vulnerability stems from inadequate input validation within the BGP packet parsing logic. When tcpdump encounters a multicast VPN BGP message, the decode_multicast_vpn() function fails to properly verify buffer limits before performing memory reads. This deficiency allows an attacker to craft specially malformed BGP packets that trigger the over-read condition. The vulnerability manifests as the parser attempting to access memory locations beyond the intended buffer boundaries, potentially exposing sensitive data from adjacent memory regions or causing the application to crash. According to CWE classification, this represents a CWE-125: Out-of-bounds Read vulnerability, which falls under the broader category of memory safety issues that have historically led to numerous security incidents in network infrastructure tools.
The operational impact of CVE-2017-13043 extends beyond simple application instability to potentially compromise network monitoring capabilities and overall system security. Since tcpdump is widely deployed across network infrastructure for packet analysis and troubleshooting, a compromised instance could provide attackers with opportunities to disrupt network operations or gain insights into network topology through memory disclosure. The vulnerability's exploitation requires an attacker to have network access and the ability to inject malicious BGP packets into the network traffic, making it particularly concerning for network operators who rely on tcpdump for security monitoring and incident response. From an ATT&CK framework perspective, this vulnerability aligns with techniques involving application layer protocol manipulation and privilege escalation through software exploitation, potentially enabling adversaries to establish persistent monitoring capabilities or disrupt network services.
Mitigation strategies for CVE-2017-13043 primarily involve upgrading tcpdump to version 4.9.2 or later, which contains the necessary patches to address the buffer over-read condition. Network administrators should prioritize this update across all systems where tcpdump is deployed, particularly in security monitoring environments where the tool is used for network traffic analysis. Additional defensive measures include implementing network segmentation to limit exposure to potentially malicious BGP traffic, deploying intrusion detection systems that can identify malformed BGP packets, and establishing network monitoring procedures that can detect abnormal tcpdump behavior. Organizations should also consider implementing network access controls to restrict BGP peer relationships to trusted sources and maintain regular vulnerability assessment programs to identify similar issues in other network monitoring tools. The patch for this vulnerability specifically addresses the boundary checking in the decode_multicast_vpn() function, ensuring that all buffer accesses are properly validated before execution.