CVE-2017-13023 in macOS
Summary
by MITRE
The IPv6 mobility parser in tcpdump before 4.9.2 has a buffer over-read in print-mobility.c:mobility_opt_print().
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Analysis
by VulDB Data Team • 09/08/2024
The vulnerability identified as CVE-2017-13023 represents a critical buffer over-read flaw within the IPv6 mobility parser functionality of tcpdump versions prior to 4.9.2. This issue resides in the print-mobility.c source file at the mobility_opt_print() function, where improper input validation and memory handling creates a condition that allows attackers to potentially execute arbitrary code or cause denial of service through malformed IPv6 mobility options. The flaw specifically manifests when tcpdump processes network packets containing crafted mobility headers, exploiting a lack of bounds checking that enables memory access beyond allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate validation of mobility option lengths within the IPv6 mobility header parsing logic. When tcpdump encounters a mobility option, it fails to properly verify that the option length field aligns with the actual data available in the packet buffer. This discrepancy allows an attacker to construct malicious IPv6 mobility packets with oversized option fields that cause the parser to read memory locations beyond the intended buffer limits. The vulnerability operates at the protocol parsing layer, making it particularly dangerous as it can be triggered by normal network traffic without requiring special privileges or authentication. This type of flaw falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation results in an over-read rather than traditional overflow conditions. The ATT&CK framework categorizes this under T1059.007 for command and script injection, as the vulnerability could potentially enable remote code execution if exploited successfully.
The operational impact of CVE-2017-13023 extends beyond simple denial of service scenarios to include potential remote code execution capabilities that could compromise network monitoring systems. Since tcpdump is commonly deployed on network infrastructure devices and security monitoring systems, exploitation of this vulnerability could allow attackers to gain unauthorized access to network traffic analysis capabilities or cause complete system crashes. The vulnerability affects systems that process IPv6 mobility packets, which are commonly found in mobile IPv6 networks and wireless networking environments. When exploited, the buffer over-read could lead to information disclosure through memory corruption, system instability, or complete system compromise depending on the execution environment and memory layout. Network administrators responsible for security monitoring and incident response would be particularly vulnerable as tcpdump is frequently used in security tools and forensic analysis, making this a critical concern for organizations maintaining network visibility and security posture.
Mitigation strategies for CVE-2017-13023 primarily involve immediate upgrade to tcpdump version 4.9.2 or later, which includes proper bounds checking and input validation for mobility option parsing. Organizations should also implement network segmentation and access controls to limit exposure of systems running vulnerable versions of tcpdump. Additional defensive measures include deploying intrusion detection systems that can identify and block malformed IPv6 mobility packets, implementing network monitoring rules to detect unusual traffic patterns that may indicate exploitation attempts, and conducting regular security assessments of network monitoring infrastructure. The fix implemented in tcpdump 4.9.2 addresses the core issue by adding proper validation of option length fields against available buffer space, preventing the over-read condition that previously allowed memory access beyond intended boundaries. Security teams should also consider implementing network access controls that limit which systems can process IPv6 mobility traffic, reducing the attack surface for this specific vulnerability while ensuring continued network functionality and monitoring capabilities.