CVE-2017-13046 in macOS
Summary
by MITRE
The BGP parser in tcpdump before 4.9.2 has a buffer over-read in print-bgp.c:bgp_attr_print().
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Analysis
by VulDB Data Team • 09/09/2024
The vulnerability identified as CVE-2017-13046 represents a critical buffer over-read flaw within the Border Gateway Protocol parser of tcpdump network analysis tool. This issue specifically affects versions prior to 4.9.2 and manifests in the print-bgp.c source file within the bgp_attr_print() function. The vulnerability arises from inadequate input validation and bounds checking when processing BGP protocol packets, creating a scenario where maliciously crafted BGP messages can cause the application to read memory beyond allocated buffer boundaries.
The technical implementation of this flaw occurs during the parsing of BGP attributes where the tcpdump tool fails to properly validate the length field of BGP attributes before attempting to read data from the packet buffer. When an attacker sends a malformed BGP packet containing an attribute with an invalid length value, the bgp_attr_print() function proceeds to read beyond the intended buffer limits, potentially accessing uninitialized memory or memory belonging to other data structures. This over-read condition can lead to information disclosure, application crashes, or in severe cases, arbitrary code execution depending on the memory access patterns and system configuration.
From an operational perspective, this vulnerability poses significant risks to network infrastructure monitoring systems that rely on tcpdump for BGP traffic analysis. Network administrators and security professionals who use tcpdump to monitor BGP sessions for security events or network troubleshooting may find their monitoring tools compromised when processing malicious BGP traffic. The impact extends beyond simple tool crashes to potential data leakage through memory dumps, as the over-read may expose sensitive information from adjacent memory regions including authentication credentials, system state information, or other confidential data that happens to be stored in memory adjacent to the affected buffer.
The vulnerability aligns with CWE-125: "Out-of-bounds Read" which classifies this issue as a fundamental memory safety problem in software development practices. From an adversarial standpoint, this flaw maps to ATT&CK technique T1059.007: "Command and Scripting Interpreter: Python" and T1566.001: "Phishing: Spearphishing Attachment" as attackers could potentially exploit this vulnerability through network-based attacks targeting monitoring infrastructure. The weakness also corresponds to ATT&CK tactic TA0006: "Credential Access" and TA0005: "Defense Evasion" as successful exploitation could lead to credential exposure or system compromise.
Mitigation strategies for CVE-2017-13046 primarily involve upgrading tcpdump to version 4.9.2 or later where the buffer over-read has been addressed through proper bounds checking and input validation. Network administrators should also implement network segmentation and access controls to limit exposure to potentially malicious BGP traffic, while monitoring for unusual BGP packet patterns that might indicate exploitation attempts. Additionally, organizations should consider implementing intrusion detection systems that can detect and alert on malformed BGP traffic patterns that could be indicative of exploitation attempts against this vulnerability. The fix implemented in the patched version demonstrates proper defensive programming practices including validation of length fields before buffer operations, preventing the over-read condition through robust input sanitization mechanisms.