CVE-2015-8837 in FuseISO
Summary
by MITRE
Stack-based buffer overflow in the isofs_real_readdir function in isofs.c in FuseISO 20070708 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a long pathname in an ISO file.
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Analysis
by VulDB Data Team • 02/03/2019
The vulnerability identified as CVE-2015-8837 represents a critical stack-based buffer overflow flaw within the FuseISO 20070708 implementation. This issue manifests specifically within the isofs_real_readdir function located in the isofs.c source file, creating a significant security risk for systems utilizing this file system driver. The vulnerability arises from insufficient input validation when processing ISO file structures, particularly when handling pathnames that exceed predetermined buffer limits. Attackers can exploit this weakness by crafting malicious ISO files containing excessively long pathnames, thereby triggering the buffer overflow condition that compromises system stability and potentially enables remote code execution.
The technical exploitation of this vulnerability follows a well-established pattern that aligns with CWE-121 stack-based buffer overflow classifications. When the isofs_real_readdir function processes directory entries from ISO files, it fails to properly bounds-check pathname lengths before copying them into fixed-size stack buffers. This omission creates a condition where attacker-controlled data can overwrite adjacent stack memory, potentially corrupting return addresses and execution flow. The flaw operates at the kernel level within the file system driver, making it particularly dangerous as it can affect the entire operating system's file system handling capabilities. The vulnerability's impact extends beyond simple denial of service to potentially enable arbitrary code execution, representing a severe privilege escalation vector.
From an operational perspective, this vulnerability presents substantial risks to systems that utilize FuseISO for mounting ISO files, particularly in environments where untrusted ISO content is processed. The attack surface includes web applications, file sharing systems, and any platform that accepts ISO file uploads or mounts external ISO images without proper validation. The remote exploitation capability means that adversaries can trigger the vulnerability through network-based attacks without requiring local access to the target system. This characteristic significantly expands the potential attack vectors and makes the vulnerability particularly attractive to threat actors seeking to compromise systems through remote means. The vulnerability's exploitation can result in complete system compromise, making it a critical concern for enterprise security teams.
Mitigation strategies for CVE-2015-8837 should prioritize immediate patching of affected FuseISO implementations, as the vulnerability has been addressed through official updates that implement proper bounds checking and input validation. Organizations should also implement network segmentation and access controls to limit exposure to potentially malicious ISO content, particularly in environments where user-uploaded files are processed. Additional protective measures include deploying file system monitoring solutions that can detect anomalous pathname lengths and implementing strict file validation policies for ISO content. Security professionals should consider implementing intrusion detection systems that can identify patterns consistent with buffer overflow exploitation attempts. The vulnerability's classification under ATT&CK technique T1059.007 for command and scripting interpreter demonstrates the potential for lateral movement and persistent access once exploitation is successful, further emphasizing the importance of comprehensive mitigation strategies. System administrators should also conduct thorough vulnerability assessments to identify all instances of FuseISO installations and ensure complete remediation across their infrastructure.