CVE-2010-1917 in PHP
Summary
by MITRE
Stack consumption vulnerability in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allows context-dependent attackers to cause a denial of service (PHP crash) via a crafted first argument to the fnmatch function, as demonstrated using a long string.
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Analysis
by VulDB Data Team • 09/13/2021
The vulnerability identified as CVE-2010-1917 represents a stack consumption issue affecting PHP versions 5.2 through 5.2.13 and 5.3 through 5.3.2. This flaw resides within the fnmatch function implementation and demonstrates how seemingly benign input processing can lead to critical system instability. The vulnerability operates through a context-dependent attack vector where malicious input triggers excessive stack memory consumption, ultimately resulting in PHP process termination and service disruption.
The technical mechanism behind this vulnerability involves the fnmatch function's handling of specially crafted input strings that cause recursive or deeply nested stack operations. When processing a long string as the first argument, the function's internal algorithms consume stack space disproportionately to the input size, creating a stack exhaustion condition. This behavior aligns with CWE-123, which describes weaknesses related to the consumption of stack resources in a manner that can be exploited for denial of service attacks. The vulnerability specifically targets the stack-based memory management within PHP's interpreter, where the function's recursive pattern processing leads to uncontrolled stack growth.
From an operational perspective, this vulnerability presents significant risk to web applications relying on PHP processing. Attackers can exploit this weakness by submitting carefully constructed input to any application using fnmatch function calls, potentially causing multiple PHP processes to crash simultaneously. The impact extends beyond individual application failures to encompass broader service availability concerns, particularly in high-traffic environments where multiple concurrent requests could trigger cascading failures. This vulnerability directly maps to ATT&CK technique T1499.004, which covers network denial of service attacks, and demonstrates how application-level flaws can be leveraged to achieve system-level disruption.
Mitigation strategies for CVE-2010-1917 require immediate version upgrading to PHP 5.2.14 or 5.3.3, which contain the patched fnmatch implementation. Organizations should also implement input validation measures that limit the length of strings processed by fnmatch functions, particularly when handling user-supplied data. Additionally, deploying web application firewalls with content inspection capabilities can help detect and block malicious input patterns before they reach vulnerable PHP functions. System administrators should monitor PHP process behavior for unusual stack consumption patterns and implement resource limits to prevent complete service exhaustion. The vulnerability highlights the importance of regular security updates and proper input sanitization practices in preventing exploitation of stack-based vulnerabilities.