CVE-2002-1174 in Fetchmail
Summary
by MITRE
Buffer overflows in Fetchmail 6.0.0 and earlier allow remote attackers to cause a denial of service (crash) or execute arbitrary code via (1) long headers that are not properly processed by the readheaders function, or (2) via long Received: headers, which are not properly parsed by the parse_received function.
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Analysis
by VulDB Data Team • 05/29/2019
The vulnerability identified as CVE-2002-1174 represents a critical buffer overflow issue affecting Fetchmail versions 6.0.0 and earlier, presenting significant security risks to email processing systems. This flaw manifests in two distinct attack vectors that exploit improper handling of email header data during the parsing process. The vulnerability specifically targets the readheaders function and the parse_received function, both of which are fundamental components responsible for processing incoming email messages. When these functions encounter malformed or excessively long header data, they fail to properly validate input boundaries, creating opportunities for buffer overflow conditions that can be exploited remotely by malicious actors.
The technical implementation of this vulnerability stems from insufficient input validation and boundary checking within the email parsing routines. The readheaders function processes email headers without adequate safeguards against excessively long input sequences, while the parse_received function demonstrates similar weaknesses when handling Received: headers. Both functions operate under the assumption that header data will conform to expected length parameters, failing to implement proper bounds checking mechanisms. This design flaw allows attackers to craft specially formatted email messages containing oversized header fields that exceed allocated buffer space, resulting in memory corruption that can trigger program crashes or potentially enable arbitrary code execution. The vulnerability operates at the application layer and requires no authentication to exploit, making it particularly dangerous in environments where email servers process untrusted input from external sources.
From an operational impact perspective, this vulnerability creates severe consequences for affected systems, including potential denial of service conditions that can disrupt email services and compromise system availability. The remote exploit capability means that attackers can target vulnerable systems from external networks without requiring physical access or local privileges, making the attack surface particularly broad. When successfully exploited, the buffer overflow conditions can cause fetchmail processes to crash, leading to complete service interruption, or in more sophisticated attacks, allow attackers to execute arbitrary code with the privileges of the fetchmail process. This could result in unauthorized access to email accounts, data exfiltration, or further compromise of the underlying system infrastructure. The vulnerability affects systems that rely on Fetchmail for email retrieval and processing, making it relevant to organizations with email server deployments, automated email handling systems, and network infrastructure that depends on this software component.
Security mitigations for CVE-2002-1174 should prioritize immediate software updates to Fetchmail versions that address these buffer overflow conditions. Organizations should implement network segmentation and access controls to limit exposure of vulnerable systems to untrusted email sources. Input validation measures including header length restrictions and rate limiting for email processing can provide additional defense-in-depth layers. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, addressing heap-based buffer overflow scenarios, both of which are common attack patterns in email processing applications. From an ATT&CK framework perspective, this vulnerability maps to T1190, targeting vulnerabilities in email servers, and T1059, involving command and scripting interpreters, as attackers may leverage the compromised system for further malicious activities. System administrators should also implement monitoring solutions to detect unusual email processing patterns that might indicate exploitation attempts and establish robust patch management procedures to ensure timely deployment of security updates across all affected systems.