CVE-2005-1267 in tcpdump
Summary
by MITRE
The bgp_update_print function in tcpdump 3.x does not properly handle a -1 return value from the decode_prefix4 function, which allows remote attackers to cause a denial of service (infinite loop) via a crafted BGP packet.
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Analysis
by VulDB Data Team • 07/04/2025
The vulnerability identified as CVE-2005-1267 resides within tcpdump version 3.x, specifically within the bgp_update_print function that processes Border Gateway Protocol packets. This flaw represents a classic input validation issue where the software fails to properly handle error conditions returned by underlying decoding functions. The decode_prefix4 function, which is responsible for parsing IPv4 prefix information within BGP updates, returns a -1 value to indicate parsing failure or error conditions. However, the bgp_update_print function does not adequately check for this specific return value, creating a critical gap in the software's error handling mechanisms.
The technical implementation of this vulnerability stems from improper boundary condition checking within the BGP packet parsing logic. When tcpdump encounters a malformed BGP packet with specific characteristics, the decode_prefix4 function legitimately returns -1 to signal that it cannot properly decode the prefix information. The bgp_update_print function, however, treats this return value as a valid length indicator and proceeds with processing, leading to a situation where the loop condition for parsing BGP attributes becomes infinite. This creates an unbounded iteration that consumes system resources and effectively renders the tcpdump process unresponsive.
From an operational perspective, this vulnerability presents a significant denial of service risk that can be exploited by remote attackers without requiring authentication or privileged access. An attacker can craft a malicious BGP packet with malformed prefix information that triggers the infinite loop condition, causing tcpdump to consume excessive CPU cycles and potentially crash the system or render network monitoring capabilities ineffective. The impact extends beyond simple service disruption as it affects network security monitoring infrastructure that relies on tcpdump for packet analysis and intrusion detection.
The vulnerability aligns with CWE-691, which addresses insufficient control flow management, specifically focusing on inadequate handling of error return values. This weakness enables an attacker to manipulate program execution flow through carefully crafted input data. The attack pattern corresponds to the ATT&CK technique T1499.004, which involves network disruption through resource exhaustion, where the infinite loop consumes system resources to deny service to legitimate users. The flaw also demonstrates characteristics of CWE-398, indicating poor code quality and insufficient error handling that could lead to unintended program behavior.
Mitigation strategies for CVE-2005-1267 should prioritize immediate patching of tcpdump installations to versions that properly handle the -1 return value from decode_prefix4. Organizations should implement network segmentation and access controls to limit exposure to potentially malicious BGP traffic. Additionally, deploying intrusion detection systems with signature-based detection for malformed BGP packets can help identify and block exploitation attempts. System administrators should monitor for unusual CPU utilization patterns that might indicate exploitation of this vulnerability. Regular security updates and vulnerability assessments should be conducted to identify similar error handling weaknesses in network monitoring tools and ensure proper boundary condition validation is implemented throughout the codebase.