CVE-2005-2796 in Squid
Summary
by MITRE
The sslConnectTimeout function in ssl.c for Squid 2.5.STABLE10 and earlier allows remote attackers to cause a denial of service (segmentation fault) via certain crafted requests.
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Analysis
by VulDB Data Team • 07/04/2019
The vulnerability identified as CVE-2005-2796 represents a critical denial of service flaw within the Squid proxy server software version 2.5.STABLE10 and earlier releases. This issue specifically targets the sslConnectTimeout function located in the ssl.c source file, demonstrating how improper handling of SSL connections can lead to system instability and service disruption. The vulnerability operates through crafted requests that exploit a segmentation fault condition, effectively crashing the proxy server and rendering it unavailable to legitimate users. Such a flaw presents significant operational risks for organizations relying on Squid as a core networking component for web traffic management and caching services.
The technical implementation of this vulnerability stems from inadequate input validation and error handling within the SSL connection timeout mechanism. When the sslConnectTimeout function processes certain malformed or specially crafted SSL requests, it fails to properly manage memory allocation or connection state transitions, leading to a segmentation fault that terminates the process. This type of vulnerability falls under the category of improper error handling as classified by CWE-252, where the system does not adequately validate or sanitize inputs before processing them in security-sensitive contexts. The flaw demonstrates a classic buffer overflow or memory corruption pattern that occurs during SSL handshake processing, particularly when the proxy attempts to establish or timeout SSL connections.
From an operational perspective, this vulnerability creates substantial risk for organizations utilizing Squid as their primary web proxy solution. Attackers can exploit this weakness to perform denial of service attacks against critical infrastructure, potentially disrupting business operations and user access to web resources. The impact extends beyond simple service interruption as it can affect downstream applications and services that depend on uninterrupted proxy connectivity. The vulnerability is particularly dangerous in environments where Squid serves as a gateway for corporate or public web access, as it could be leveraged to create widespread service disruption. Network administrators face the challenge of maintaining availability while managing the risk of exploitation, especially since the attack requires minimal sophistication to execute successfully.
Organizations should implement immediate mitigations including upgrading to Squid versions 2.5.STABLE11 or later, where this vulnerability has been addressed through proper input validation and error handling mechanisms. System administrators should also consider implementing network-level protections such as rate limiting and connection tracking to reduce the impact of potential exploitation attempts. The remediation process should include thorough testing of updated configurations to ensure that proxy functionality remains intact while addressing the specific memory handling issues. Additionally, monitoring systems should be enhanced to detect unusual connection patterns or segmentation fault occurrences that may indicate attempted exploitation. This vulnerability highlights the importance of maintaining current security patches and implementing comprehensive vulnerability management processes to prevent similar issues in other network services and applications.