CVE-2017-12900 in macOS
Summary
by MITRE
Several protocol parsers in tcpdump before 4.9.2 could cause a buffer over-read in util-print.c:tok2strbuf().
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/05/2023
The vulnerability identified as CVE-2017-12900 represents a critical buffer over-read flaw affecting tcpdump versions prior to 4.9.2. This issue resides within the protocol parsers of tcpdump, a widely-used network packet analyzer tool that plays a fundamental role in network security monitoring and forensic analysis. The vulnerability specifically manifests in the util-print.c file at the tok2strbuf() function, which is responsible for converting token values to string representations during packet processing. The flaw occurs when tcpdump processes malformed network packets that contain crafted data structures, leading to improper memory access patterns that exceed allocated buffer boundaries.
The technical implementation of this vulnerability stems from inadequate input validation and boundary checking within the token string conversion routine. When tcpdump encounters network packets with malformed or unexpected data formats, particularly those involving protocol-specific fields that exceed expected length constraints, the tok2strbuf() function fails to properly validate buffer limits before performing memory reads. This allows attackers to craft specially formatted packets that, when processed by the vulnerable tcpdump version, trigger unauthorized memory access patterns. The buffer over-read condition can result in information disclosure, application crashes, or potentially more severe consequences depending on the execution environment and memory layout.
From an operational perspective, this vulnerability poses significant risks to network security infrastructure that relies on tcpdump for monitoring and analysis purposes. Security operations centers, network forensics teams, and penetration testing environments that utilize older tcpdump versions may be vulnerable to exploitation by attackers who can craft malicious network traffic to trigger the buffer over-read condition. The impact extends beyond simple application crashes, as the over-read behavior could potentially expose sensitive memory contents to attackers, creating information disclosure risks that could compromise network security monitoring capabilities. This vulnerability particularly affects systems where tcpdump is used in automated monitoring scenarios or when processing untrusted network traffic from external sources.
Mitigation strategies for CVE-2017-12900 primarily focus on immediate version upgrades to tcpdump 4.9.2 or later releases that contain the necessary patches addressing the buffer over-read condition. System administrators should prioritize updating tcpdump installations across all network monitoring and security infrastructure, particularly in environments where the tool processes untrusted network traffic. Additionally, network segmentation and access control measures should be implemented to limit exposure, while regular security assessments should verify that all tcpdump instances are properly updated and monitored. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of improper input validation that can lead to memory safety issues. Organizations should also consider implementing network traffic filtering rules that can detect and block malformed packets that might trigger this specific vulnerability, as part of broader defensive measures against similar buffer overflow conditions.