CVE-2004-1018 in PHP
Summary
by MITRE
Multiple integer handling errors in PHP before 4.3.10 allow attackers to bypass safe mode restrictions, cause a denial of service, or execute arbitrary code via (1) a negative offset value to the shmop_write function, (2) an "integer overflow/underflow" in the pack function, or (3) an "integer overflow/underflow" in the unpack function. NOTE: this issue was originally REJECTed by its CNA before publication, but that decision is in active dispute. This candidate may change significantly in the future as a result of further discussion.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/31/2025
The vulnerability described in CVE-2004-1018 represents a critical class of integer handling flaws that affected PHP versions prior to 4.3.10, fundamentally compromising the security and stability of web applications running on PHP platforms. These vulnerabilities stem from improper validation and handling of integer values within core PHP functions, creating multiple attack vectors that could be exploited by malicious actors to bypass security mechanisms and execute unauthorized operations. The issue specifically targets the fundamental data processing capabilities of PHP, making it particularly dangerous as it affects core functionality used extensively across web applications.
The technical flaw manifests through three distinct attack vectors that all involve improper integer handling within PHP's core functions. The first vulnerability occurs in the shmop_write function where negative offset values can be passed, potentially allowing attackers to manipulate shared memory operations and bypass safe mode restrictions that are designed to limit file system access. The second and third vulnerabilities involve integer overflow and underflow conditions within the pack and unpack functions respectively, which are commonly used for data serialization and manipulation. These integer handling errors occur when PHP processes values that exceed the normal range of integer representation, creating situations where the system interprets these values incorrectly, leading to unpredictable behavior that can be exploited for malicious purposes.
The operational impact of these vulnerabilities extends beyond simple denial of service conditions to include complete system compromise through arbitrary code execution. When attackers exploit these integer handling errors, they can manipulate the memory layout of PHP processes, potentially leading to buffer overflows, memory corruption, or privilege escalation scenarios. The ability to bypass safe mode restrictions is particularly concerning as it undermines fundamental security mechanisms designed to contain PHP execution within predetermined boundaries, allowing attackers to access restricted files, execute system commands, or otherwise compromise the underlying system. These vulnerabilities essentially provide attackers with multiple pathways to gain unauthorized access to systems and execute malicious code with the privileges of the web server process.
The security implications of CVE-2004-1018 align with CWE-190, which describes integer overflow and underflow conditions, and reflect the broader category of CWE-129, which addresses insufficient validation of integer limits. From an attack perspective, these vulnerabilities map to techniques described in the MITRE ATT&CK framework under T1059 for command and script injection, and T1068 for exploit for privilege escalation. The vulnerabilities demonstrate how seemingly minor implementation flaws in core system functions can create significant security risks, particularly when they involve memory manipulation and data processing operations that are fundamental to application functionality. Organizations running vulnerable PHP versions were exposed to immediate risk of compromise, as these vulnerabilities could be exploited through simple input manipulation without requiring special privileges or advanced exploitation techniques.
The recommended mitigation strategy involves immediate upgrading to PHP version 4.3.10 or later, which contains the necessary patches to address these integer handling errors. System administrators should also implement additional monitoring and input validation measures to detect and prevent exploitation attempts. The vulnerability highlights the importance of thorough input validation and proper integer handling in security-critical applications, particularly in languages like PHP that are widely used for web application development. Organizations should conduct comprehensive vulnerability assessments to identify any applications running on affected PHP versions and ensure proper patch management procedures are in place to prevent similar issues from occurring in the future.