This essay explores the vulnerabilities associated with Apache HTTPD 2.4.18, analyzing the specific Common Vulnerabilities and Exposures (CVEs) affecting it, the architectural risks it inherited, and the implications for systems that remain dependent on this legacy code base.
Additionally, the default configuration of 2.4.18 often left servers exposed to Slowloris-type attacks. While Apache has always been susceptible to Slow HTTP DoS attacks due to its thread-per-connection architecture, the mitigation modules available at the time (like mod_reqtimeout ) required explicit configuration. Default installs of 2.4.18 frequently lacked these hardening parameters, making the "vulnerability" not a code bug, but a configuration oversight. apache httpd 2.4.18 vulnerability
: A local user with limited permissions (such as through a script on the server) could manipulate the scoreboard to execute arbitrary code with root privileges . Severity : High (CVSS 8.2). 4. Memory Leak in HTTP/2 (CVE-2019-10082) Default installs of 2
: Attackers can perform a padding oracle attack to decrypt session cookies or even modify them to include attacker-specified data. This could lead to session hijacking or unauthorized access. Severity : High (CVSS 7.5). 3. Privilege Escalation (CVE-2019-0211) the architectural risks it inherited
The most prominent vulnerability linked to the immediate release cycle of 2.4.18 is . This flaw specifically targeted the mod_cgid module, which is responsible for managing CGI (Common Gateway Interface) scripts.
: The mod_session_crypto module does not use a mechanism to verify the integrity of encrypted session data stored in a user's browser.
This is perhaps the most "interesting" flaw for this specific version. The HTTP/2 implementation in 2.4.18 (and earlier) allowed a remote attacker to cause a Denial of Service (DoS) by sending specifically crafted HTTP/2 requests that led to excessive memory consumption.