CVE-2007-2872 in PHP
Summary
by MITRE
Multiple integer overflows in the chunk_split function in PHP 5 before 5.2.3 and PHP 4 before 4.4.8 allow remote attackers to cause a denial of service (crash) or execute arbitrary code via the (1) chunks, (2) srclen, and (3) chunklen arguments.
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Analysis
by VulDB Data Team • 04/20/2025
The vulnerability identified as CVE-2007-2872 represents a critical security flaw in PHP's chunk_split function that affects versions prior to 5.2.3 and 4.4.8. This issue manifests through multiple integer overflow conditions that can be exploited by remote attackers to either crash the web server or execute arbitrary code on the affected system. The vulnerability specifically targets the chunk_split function which is commonly used in PHP applications for splitting strings into smaller chunks, making it a frequent target for exploitation in web applications.
The technical implementation of this vulnerability stems from insufficient input validation within the chunk_split function where integer overflows occur when processing the chunks, srclen, and chunklen arguments. These integer overflows create conditions where malicious input can cause the application to allocate insufficient memory or perform invalid memory operations, leading to potential code execution or system crashes. The flaw exists at the core level of PHP's string manipulation functions, making it particularly dangerous as it can be triggered through normal web application usage patterns. This vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions that can lead to memory corruption and arbitrary code execution.
The operational impact of CVE-2007-2872 extends beyond simple denial of service scenarios to include potential remote code execution capabilities that could allow attackers to compromise entire web servers. When exploited successfully, the vulnerability can cause web applications to crash, leading to service disruption, or more critically, enable attackers to execute malicious code with the privileges of the web server process. This represents a significant threat to web application security as the chunk_split function is widely used across PHP applications, making the attack surface extensive. The vulnerability falls under the ATT&CK technique T1203, which involves exploiting software vulnerabilities to gain unauthorized access or execute malicious code.
Mitigation strategies for this vulnerability require immediate patching of affected PHP installations to versions 5.2.3 or 4.4.8 and later, as these releases contain the necessary fixes for the integer overflow conditions. Organizations should also implement input validation measures to prevent malformed data from reaching the chunk_split function, though this approach is less reliable than proper patching. Network-based mitigations such as web application firewalls can help detect and block exploitation attempts, but they do not address the root cause. System administrators should monitor for exploitation attempts and implement proper logging to detect when the vulnerability is being targeted, as the exploitation often manifests as unusual memory usage patterns or application crashes that can serve as indicators of compromise.