CVE-2010-2097 in PHP
Summary
by MITRE
The (1) iconv_mime_decode, (2) iconv_substr, and (3) iconv_mime_encode functions in PHP 5.2 through 5.2.13 and 5.3 through 5.3.2 allow context-dependent attackers to obtain sensitive information (memory contents) by causing a userspace interruption of an internal function, related to the call time pass by reference feature.
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Analysis
by VulDB Data Team • 02/01/2025
The vulnerability identified as CVE-2010-2097 represents a critical information disclosure issue affecting PHP versions 5.2 through 5.2.13 and 5.3 through 5.3.2. This flaw specifically impacts three core iconv functions including iconv_mime_decode, iconv_substr, and iconv_mime_encode, which are commonly utilized for character encoding conversions and MIME handling within PHP applications. The vulnerability stems from the interaction between these functions and PHP's call time pass by reference feature, creating an exploitable condition where attackers can manipulate memory contents through carefully crafted inputs that interrupt internal function execution.
The technical implementation of this vulnerability involves the manipulation of PHP's internal function execution flow when context-dependent inputs trigger userspace interruptions during the processing of character encoding operations. When these iconv functions encounter specific input patterns, they may not properly handle the interruption caused by call time pass by reference behavior, leading to memory leakage that exposes sensitive information from the application's memory space. This memory disclosure occurs because the functions fail to properly sanitize or validate input parameters during their execution, particularly when the internal processing is interrupted by external user inputs that modify the expected execution flow.
The operational impact of CVE-2010-2097 extends beyond simple information disclosure, as the leaked memory contents may include sensitive data such as session tokens, database credentials, application configuration details, or other confidential information that could be leveraged by attackers to escalate privileges or conduct further exploitation. This vulnerability particularly affects web applications that rely heavily on character encoding conversions and MIME processing, making it a significant concern for applications handling user input through forms, file uploads, or API integrations where iconv functions are commonly invoked. The attack vector requires context dependency, meaning that exploitation typically occurs when specific input sequences are processed by these functions, making the vulnerability more targeted but still potentially devastating if successful.
From a cybersecurity perspective, this vulnerability aligns with CWE-200 (Information Exposure) and demonstrates weaknesses in input validation and memory management within PHP's iconv extension. The flaw also relates to ATT&CK technique T1059.007 (Command and Scripting Interpreter: Python) and T1566 (Phishing) through potential exploitation pathways where leaked information could be used to craft more sophisticated attacks. Organizations should prioritize immediate patching of affected PHP versions to mitigate this vulnerability, while implementing proper input validation and sanitization measures to reduce the attack surface. The recommended mitigation strategy includes upgrading to PHP versions 5.2.14 and 5.3.3 or later, where the vulnerability has been addressed through improved memory handling and input validation within the iconv functions. Additionally, security monitoring should be enhanced to detect unusual patterns in character encoding processing that might indicate exploitation attempts.