CVE-2007-1887 in PHP
Summary
by MITRE
Buffer overflow in the sqlite_decode_binary function in the bundled sqlite library in PHP 4 before 4.4.5 and PHP 5 before 5.2.1 allows context-dependent attackers to execute arbitrary code via an empty value of the in parameter, as demonstrated by calling the sqlite_udf_decode_binary function with a 0x01 character.
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Analysis
by VulDB Data Team • 07/18/2019
The vulnerability described in CVE-2007-1887 represents a critical buffer overflow condition within the sqlite_decode_binary function of PHP's bundled sqlite library. This flaw exists in PHP versions prior to 4.4.5 and 5.2.1, making a significant portion of web applications using these versions susceptible to remote code execution attacks. The vulnerability specifically manifests when the sqlite_udf_decode_binary function processes input containing a 0x01 character, creating a scenario where attackers can manipulate the function's behavior to overwrite adjacent memory locations. The buffer overflow occurs due to insufficient bounds checking in the sqlite_decode_binary implementation, allowing malicious input to exceed allocated memory boundaries and potentially execute arbitrary code on the affected system.
The technical exploitation of this vulnerability leverages the improper handling of binary data within PHP's sqlite extension, which operates under the context-dependent attack model where the attacker must have the ability to influence the input parameters passed to the sqlite_udf_decode_binary function. This function is designed to decode binary data for database operations, but the lack of proper input validation creates a pathway for attackers to craft malicious payloads that trigger the buffer overflow condition. The specific trigger involves passing an empty value for the in parameter combined with a 0x01 character, which causes the underlying sqlite library to mishandle the data processing and subsequently overflow the allocated buffer space. This type of vulnerability falls under CWE-121, which categorizes buffer overflow conditions where insufficient bounds checking allows memory corruption, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution.
The operational impact of this vulnerability extends beyond simple code execution, as it can lead to complete system compromise when exploited successfully. Attackers can leverage this vulnerability to gain unauthorized access to web servers running vulnerable PHP versions, potentially escalating privileges and establishing persistent backdoors within the affected infrastructure. The vulnerability affects web applications that utilize PHP's sqlite extension for database operations, making it particularly dangerous in environments where database functions are frequently called with user-supplied data. Organizations running vulnerable PHP versions face significant risk of data breaches, service disruption, and potential regulatory compliance violations, as this vulnerability can be exploited remotely without requiring authentication. The exploitation requires minimal privileges and can be automated, making it a preferred target for malicious actors seeking to compromise web applications at scale. Security teams must prioritize patching affected systems and implementing proper input validation measures to prevent exploitation attempts that could result in unauthorized access to sensitive data and system resources.