CVE-2007-0247 in Squid
Summary
by MITRE
squid/src/ftp.c in Squid before 2.6.STABLE7 allows remote FTP servers to cause a denial of service (core dump) via crafted FTP directory listing responses, possibly related to the (1) ftpListingFinish and (2) ftpHtmlifyListEntry functions.
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Analysis
by VulDB Data Team • 12/28/2024
The vulnerability identified as CVE-2007-0247 affects the Squid proxy server software, specifically within the ftp.c source file version prior to 2.6.STABLE7. This issue represents a critical denial of service vulnerability that can be exploited by remote FTP servers to crash the Squid proxy daemon, resulting in core dump generation and service disruption. The vulnerability manifests when the proxy server processes crafted FTP directory listing responses from malicious FTP servers, causing it to enter an unstable state that ultimately leads to system crash.
The technical flaw resides in the ftpListingFinish and ftpHtmlifyListEntry functions within Squid's FTP handling module. These functions fail to properly validate or sanitize FTP directory listing data received from remote servers, creating a buffer overflow or memory corruption condition when processing malformed responses. The vulnerability is particularly dangerous because it can be triggered remotely without requiring authentication or special privileges from the attacker. The crafted FTP directory listings contain specially constructed data that causes the Squid proxy to improperly handle the response, leading to memory corruption and subsequent crash of the proxy process.
From an operational impact perspective, this vulnerability severely compromises the availability of services that depend on Squid as a proxy server. Organizations relying on Squid for web filtering, caching, or anonymous proxy services face significant risk of service interruption when attacked. The denial of service can affect multiple users simultaneously, as the proxy daemon crash impacts all ongoing connections. The core dump generation indicates that the system may also experience resource exhaustion and potential information disclosure through the crash dump files, which could contain sensitive data from memory segments.
The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and relates to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should implement immediate mitigation strategies including upgrading to Squid version 2.6.STABLE7 or later, which contains the necessary patches to properly validate FTP directory listing responses. Network segmentation and filtering rules can be implemented to restrict FTP traffic to trusted sources, while monitoring systems should be configured to detect unusual crash patterns or core dump generation. Additionally, implementing intrusion detection systems that can identify crafted FTP responses and deploying automated patch management processes will help prevent exploitation of this vulnerability across enterprise environments.