CVE-2006-4548 in e107
Summary
by MITRE
e107 0.75 and earlier does not properly unset variables when the input data includes a numeric parameter with a value matching an alphanumeric parameter s hash value, which allows remote attackers to execute arbitrary PHP code via the tinyMCE_imglib_include image/jpeg parameter in e107_handlers/tiny_mce/plugins/ibrowser/ibrowser.php, as demonstrated by a multipart/form-data request. NOTE: it could be argued that this vulnerability is due to a bug in the unset PHP command (CVE-2006-3017) and the proper fix should be in PHP; if so, then this should not be treated as a vulnerability in e107.
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Analysis
by VulDB Data Team • 07/11/2019
The vulnerability described in CVE-2006-4548 represents a critical security flaw in e107 version 0.75 and earlier, specifically within the tinyMCE image library handling functionality. This issue stems from improper variable handling during input validation processes, creating a condition where numeric parameters can interfere with alphanumeric parameter processing. The vulnerability manifests in the e107_handlers/tiny_mce/plugins/ibrowser/ibrowser.php file when processing multipart/form-data requests containing the tinyMCE_imglib_include parameter with image/jpeg content type. The core technical flaw occurs when the application attempts to unset variables but fails to properly handle cases where numeric input values match the hash values of alphanumeric parameters, creating a potential code execution vector.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows remote attackers to execute arbitrary PHP code on vulnerable systems. This represents a severe security risk that could enable attackers to gain full control over affected web servers, potentially leading to data breaches, system compromise, and unauthorized access to sensitive information. The vulnerability specifically targets the variable unsetting mechanism within PHP's handling of form data, where the interaction between numeric and alphanumeric parameter values creates unexpected behavior that can be exploited to bypass intended security controls. This flaw operates at the intersection of input validation and memory management, creating a dangerous condition where attacker-controlled data can manipulate the application's internal state.
The technical exploitation requires careful crafting of multipart/form-data requests that leverage PHP's hash collision behavior in variable handling. Attackers must construct requests where numeric parameter values align with alphanumeric parameter hash values, effectively creating a condition where the unset operation fails to properly remove variables from memory. This vulnerability directly relates to CWE-121, which addresses buffer overflow conditions, and CWE-122, which covers buffer overflow in heap. The attack pattern aligns with ATT&CK technique T1190, which involves exploiting vulnerabilities in web applications, and T1059, which focuses on command and scripting interpreters. The vulnerability demonstrates how improper input validation and variable handling can create persistent security weaknesses that persist across different application components.
While the vulnerability description acknowledges that it could potentially be classified as a PHP-level issue (CVE-2006-3017) rather than an e107-specific flaw, the practical impact remains significant for affected systems. The proper mitigation strategy involves both immediate application-level patches to address variable handling and broader PHP updates to resolve underlying hash collision issues. Organizations should implement input validation measures that prevent numeric parameter interference with alphanumeric processing, while also ensuring that all systems running e107 are updated to versions that properly handle this edge case. The vulnerability highlights the importance of thorough testing for hash collision scenarios in applications that process user input through complex variable manipulation mechanisms, particularly those involving file upload and image processing functionality.