CVE-2013-1912 in HAProxy
Summary
by MITRE
Buffer overflow in HAProxy 1.4 through 1.4.22 and 1.5-dev through 1.5-dev17, when HTTP keep-alive is enabled, using HTTP keywords in TCP inspection rules, and running with rewrite rules that appends to requests, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via crafted pipelined HTTP requests that prevent request realignment from occurring.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability identified as CVE-2013-1912 represents a critical buffer overflow flaw affecting HAProxy versions ranging from 1.4 through 1.4.22 and 1.5-dev through 1.5-dev17. This issue specifically manifests when the proxy server operates with HTTP keep-alive functionality enabled while simultaneously processing TCP inspection rules that utilize HTTP keywords and executing rewrite rules that append data to incoming requests. The flaw operates at the intersection of multiple processing layers within the HAProxy architecture, creating a complex attack surface that leverages the interaction between request parsing, buffer management, and protocol inspection mechanisms.
The technical exploitation of this vulnerability occurs through carefully crafted pipelined HTTP requests that manipulate the request realignment process within HAProxy's processing pipeline. When these specific conditions are met, the buffer overflow occurs during the handling of HTTP requests that have been modified by rewrite rules, causing the application to crash or potentially allowing arbitrary code execution. The vulnerability stems from insufficient bounds checking during the processing of modified HTTP requests, where the buffer allocated for request data becomes insufficient to accommodate the appended content from rewrite operations. This flaw directly maps to CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflow scenarios, as the memory management issues can manifest in both stack and heap allocation contexts within the HAProxy processing environment.
The operational impact of this vulnerability extends beyond simple denial of service, as it potentially enables remote code execution capabilities that could allow attackers to compromise the entire HAProxy instance. When exploited successfully, the vulnerability could provide attackers with the ability to execute arbitrary commands on the affected system with the privileges of the HAProxy process, potentially leading to complete system compromise. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous in production environments where HAProxy serves as a critical load balancing and proxy infrastructure component. The vulnerability affects the fundamental integrity of the proxy service, potentially disrupting network traffic flow and creating opportunities for further lateral movement within compromised networks.
Mitigation strategies for CVE-2013-1912 should prioritize immediate patching of affected HAProxy versions to the latest stable releases that contain the necessary buffer overflow protections. Organizations should implement network segmentation and access controls to limit exposure to the vulnerable proxy configurations, particularly in environments where HTTP keep-alive and rewrite rules are actively utilized. The implementation of intrusion detection systems capable of identifying malicious pipelined HTTP request patterns can provide additional layers of defense. Security teams should also consider disabling HTTP keep-alive functionality in environments where the vulnerability cannot be immediately patched, and implementing comprehensive monitoring of HAProxy process behavior to detect potential exploitation attempts. According to ATT&CK framework, this vulnerability aligns with T1499.004 for network denial of service and T1059.007 for command and scripting interpreter, highlighting the multi-faceted attack vectors that can emerge from a single buffer overflow vulnerability in a critical infrastructure component.