CVE-2012-3505 in Tinyproxy
Summary
by MITRE
Tinyproxy 1.8.3 and earlier allows remote attackers to cause a denial of service (CPU and memory consumption) via (1) a large number of headers or (2) a large number of forged headers that trigger hash collisions predictably. bucket.
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Analysis
by VulDB Data Team • 12/31/2024
The vulnerability identified as CVE-2012-3505 affects Tinyproxy versions 1.8.3 and earlier, presenting a significant denial of service risk that can severely impact system availability. This issue stems from the proxy server's inadequate handling of HTTP headers during the processing phase, creating exploitable conditions that allow remote attackers to consume excessive system resources through carefully crafted malicious requests. The vulnerability specifically targets the hash table implementation used by Tinyproxy to manage header processing, making it susceptible to predictable hash collision attacks that can be leveraged remotely.
The technical flaw manifests when attackers send HTTP requests containing either an excessive number of headers or forged headers that are designed to create predictable hash collisions within Tinyproxy's internal data structures. This occurs because the proxy server uses a hash table to store and retrieve header information, and when hash collisions occur frequently, the performance degrades significantly as the system must handle collisions through linear probing or chaining mechanisms. The vulnerability operates at the application layer and requires no authentication or privileged access to exploit, making it particularly dangerous in networked environments where proxy servers are commonly deployed.
The operational impact of this vulnerability is severe, as it can lead to complete system unresponsiveness and resource exhaustion. When attackers exploit this flaw, they can cause the proxy server to consume excessive CPU cycles and memory resources, potentially leading to system crashes or making the service completely unavailable to legitimate users. The attack can be executed from remote locations without requiring special privileges, making it an attractive vector for denial of service attacks against systems that rely on Tinyproxy for web access control or caching services. This vulnerability particularly affects organizations that use Tinyproxy as a gateway or filtering mechanism, as the service interruption can block legitimate traffic and compromise business continuity.
The vulnerability aligns with CWE-327, which addresses weak cryptographic hashing and hash collision issues in software implementations, and can be categorized under ATT&CK technique T1499.004 for network denial of service attacks. Organizations should immediately upgrade to Tinyproxy version 1.8.4 or later, which includes patches addressing the hash collision vulnerability. Additional mitigations include implementing rate limiting on header processing, configuring resource limits for proxy server processes, and monitoring for unusual header patterns that may indicate exploitation attempts. Network administrators should also consider implementing intrusion detection systems that can identify and block malicious header sequences that trigger hash collision conditions, while ensuring that proxy server configurations enforce reasonable limits on header counts and sizes to prevent exploitation of this vulnerability.