CVE-2006-2319 in Ideal BB
Summary
by MITRE
Ideal Science Ideal BB 1.5.4a and earlier does not properly check file extensions before permitting an upload, which allows remote attackers to upload and execute an ASP script via a 0x00 character before the ".asp" portion of the filename.
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Analysis
by VulDB Data Team • 06/18/2019
The vulnerability identified as CVE-2006-2319 affects Ideal Science Ideal BB 1.5.4a and earlier versions of their bulletin board software, representing a critical security flaw in file upload validation mechanisms. This issue stems from inadequate input sanitization and file extension checking procedures within the application's upload functionality, creating a pathway for malicious actors to bypass security controls and execute arbitrary code on the affected system. The vulnerability specifically targets the file extension validation process, where the software fails to properly sanitize filenames before accepting uploads, allowing attackers to manipulate the upload process through strategic insertion of null characters.
The technical exploitation of this vulnerability relies on the manipulation of filename encoding to circumvent the standard file extension checks. Attackers can append a null character 0x00 before the .asp extension in their malicious payload, effectively bypassing the software's validation logic that typically examines file extensions for allowed types. This technique exploits a fundamental weakness in how the application processes and validates filenames, where the null character terminates string processing in many programming environments, causing the validation routine to only examine the portion of the filename before the null terminator. This creates a scenario where the system accepts the file as a legitimate .asp file while actually storing it with the null character embedded in the filename, enabling execution of the malicious code through the web server's interpretation of the file.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to the affected system through the uploaded ASP script. Once successfully uploaded and executed, the malicious script can perform various malicious activities including data exfiltration, system reconnaissance, privilege escalation, and establishment of backdoors for continued access. The vulnerability particularly affects web applications that rely on user-generated content, as it allows attackers to gain unauthorized code execution privileges that can compromise entire server infrastructures. This type of vulnerability falls under CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," and aligns with ATT&CK technique T1190 for "Exploit Public-Facing Application" and T1059.007 for "Command and Scripting Interpreter: JavaScript" when considering the web-based execution environment.
Mitigation strategies for this vulnerability require immediate implementation of robust file upload validation mechanisms that properly sanitize all user-supplied filenames and enforce strict extension checking. Organizations should implement multiple validation layers including server-side checks that examine the complete filename including any embedded characters, and should reject any uploads containing null characters or other potentially malicious sequences. The fix should involve comprehensive input validation that checks for and removes or encodes special characters including null terminators, and should enforce strict file type restrictions with whitelisting of allowed extensions rather than blacklisting. Additionally, proper file handling procedures should include storing uploaded files outside the web root directory and implementing proper file permissions to prevent execution of uploaded content. System administrators should also implement monitoring and logging of file upload activities to detect and respond to potential exploitation attempts, and should ensure that all affected systems receive immediate patch updates to address this vulnerability. The remediation process should also include comprehensive security testing of upload functionality to verify that similar vulnerabilities do not exist in other parts of the application or related systems.