CVE-2014-0098 in MacOS X
Summary
by MITRE
The log_cookie function in mod_log_config.c in the mod_log_config module in the Apache HTTP Server before 2.4.8 allows remote attackers to cause a denial of service (segmentation fault and daemon crash) via a crafted cookie that is not properly handled during truncation.
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Analysis
by VulDB Data Team • 05/08/2026
The vulnerability identified as CVE-2014-0098 represents a critical denial of service flaw within the Apache HTTP Server's mod_log_config module. This issue affects versions prior to 2.4.8 and stems from improper handling of crafted cookies during the log_cookie function execution. The vulnerability specifically manifests when the server processes log entries containing malformed cookie data that triggers a segmentation fault during truncation operations. The flaw occurs in the mod_log_config.c source file where the log_cookie function fails to adequately validate cookie content before attempting to truncate and log it, creating a condition that can be exploited by remote attackers to crash the httpd daemon.
The technical exploitation of this vulnerability leverages the server's logging mechanism to trigger a segmentation fault through specially crafted cookie values. When the mod_log_config module encounters a cookie that exceeds predetermined length limits, the truncation logic fails to properly handle the edge case of malformed cookie data. This improper handling causes the server process to attempt accessing invalid memory locations, resulting in a segmentation fault that terminates the httpd process. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow condition, though it manifests as a denial of service rather than arbitrary code execution. Attackers can remotely send HTTP requests containing malicious cookie values that, when processed by the logging module, will trigger the crash condition.
The operational impact of CVE-2014-0098 extends beyond simple service interruption, as it can be weaponized to create persistent denial of service attacks against Apache servers. The vulnerability affects the core logging functionality of the web server, meaning that any legitimate traffic that triggers the logging process could potentially cause the daemon to crash. This creates a scenario where attackers can systematically destabilize web services by sending carefully crafted requests that exploit the cookie truncation logic. The impact is particularly severe in high-traffic environments where the server's logging process is frequently invoked, as the frequency of crashes can lead to significant service degradation. From an ATT&CK perspective, this vulnerability maps to T1499.004 for Network Denial of Service and T1595.001 for Network Scanning, as it enables attackers to identify and exploit server weaknesses to disrupt availability.
Mitigation strategies for CVE-2014-0098 primarily focus on upgrading to Apache HTTP Server version 2.4.8 or later, which contains the patched implementation of the log_cookie function. System administrators should also implement input validation measures at the application level to filter suspicious cookie values before they reach the web server logging module. Additional protective measures include configuring server-side rate limiting for cookie processing, implementing proper error handling in logging modules, and monitoring for unusual crash patterns that may indicate exploitation attempts. The vulnerability highlights the importance of proper input validation in server-side components and demonstrates how seemingly benign logging functions can become attack vectors when inadequate error handling is present. Organizations should also consider implementing intrusion detection systems that can identify patterns of cookie-based attacks and establish automated monitoring for daemon crash events that may indicate exploitation of this or similar vulnerabilities.