CVE-2011-1469 in PHP
Summary
by MITRE
Unspecified vulnerability in the Streams component in PHP before 5.3.6 allows context-dependent attackers to cause a denial of service (application crash) by accessing an ftp:// URL during use of an HTTP proxy with the FTP wrapper.
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Analysis
by VulDB Data Team • 10/20/2021
The vulnerability identified as CVE-2011-1469 represents a critical flaw within PHP's Streams component that existed in versions prior to 5.3.6. This issue manifests as a denial of service condition that can be triggered through specific network protocol interactions involving FTP and HTTP proxy configurations. The vulnerability specifically affects applications that utilize PHP's stream wrappers to handle network connections, particularly when processing ftp:// URLs in environments where HTTP proxies are configured for FTP access.
The technical mechanism behind this vulnerability involves the improper handling of FTP stream contexts when HTTP proxy settings are active. When PHP attempts to access an ftp:// URL while configured to use an HTTP proxy, the Streams component fails to properly validate or manage the connection state, leading to memory corruption or invalid pointer dereferences. This flaw occurs during the initialization or processing phase of FTP stream operations, where the system does not adequately check the proxy configuration parameters or validate the connection context before proceeding with the network operation. The context-dependent nature of this vulnerability means that exploitation requires specific environmental conditions involving both FTP wrapper usage and HTTP proxy configuration, making it less universally exploitable but still dangerous in affected configurations.
The operational impact of CVE-2011-1469 extends beyond simple application crashes, potentially disrupting service availability for systems running vulnerable PHP versions. Attackers can leverage this vulnerability to repeatedly crash PHP applications that process user-supplied URLs or perform FTP operations through HTTP proxies, effectively causing a denial of service condition that can impact legitimate users and system availability. This vulnerability particularly affects web applications that handle file uploads, remote content fetching, or any functionality that relies on PHP's ability to connect to remote FTP servers through proxy configurations. The flaw can be exploited through various attack vectors including web forms, API endpoints, or any interface that accepts URLs for processing, making it a significant concern for web application security.
Mitigation strategies for CVE-2011-1469 primarily involve upgrading to PHP version 5.3.6 or later, which includes patches addressing the stream handling inconsistencies in FTP proxy configurations. System administrators should also implement proper input validation and sanitization to prevent malicious URL inputs from reaching the FTP stream processing functions. Network-level protections such as firewall rules or proxy server configurations can help limit exposure by restricting direct FTP access or implementing additional validation layers. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and may map to ATT&CK technique T1499.004 for network denial of service attacks. Organizations should also consider implementing monitoring solutions to detect unusual application crash patterns that might indicate exploitation attempts, and maintain regular security assessments to identify similar vulnerabilities in their PHP applications and dependencies.