CVE-2017-8305 in UDFclient
Summary
by MITRE
The UDFclient (before 0.8.8) custom strlcpy implementation has a buffer overflow. UDFclient's strlcpy is used only on systems with a C library (e.g., glibc) that lacks its own strlcpy.
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Analysis
by VulDB Data Team • 09/21/2020
The vulnerability identified as CVE-2017-8305 affects the UDFclient software version prior to 0.8.8, specifically targeting a custom implementation of the strlcpy function that is utilized when the underlying system's C library does not provide this functionality. This issue represents a classic buffer overflow vulnerability that arises from improper bounds checking during string copying operations. The UDFclient software implements its own strlcpy function as a fallback mechanism for systems using glibc or similar C libraries that lack native strlcpy support, creating a potential attack surface that security researchers must carefully consider.
The technical flaw manifests in the custom strlcpy implementation where the function fails to properly validate the length of source strings against the destination buffer capacity. This oversight allows attackers to provide input strings that exceed the allocated buffer space, resulting in memory corruption that can be exploited to execute arbitrary code or cause denial of service conditions. The vulnerability specifically impacts systems where the native C library does not include strlcpy, forcing the application to rely on the custom implementation that contains the buffer overflow flaw. This design decision creates a security risk that is particularly concerning given the widespread use of glibc-based systems.
The operational impact of this vulnerability extends beyond simple memory corruption, as it can enable attackers to perform remote code execution or system compromise when the vulnerable UDFclient application processes untrusted input data. The buffer overflow occurs during string operations that are commonly performed when handling user inputs, file names, or network data, making the attack surface quite broad. Security practitioners should note that this vulnerability is particularly dangerous in environments where UDFclient is used to process external data or where it runs with elevated privileges. The exploitation potential is further enhanced by the fact that this is a custom implementation rather than a well-known system function, making it less likely to be detected by standard security scanning tools that may not recognize the specific pattern of the flawed implementation.
Mitigation strategies for CVE-2017-8305 should prioritize upgrading to UDFclient version 0.8.8 or later, which contains the corrected strlcpy implementation. Organizations should also implement input validation measures to prevent overly long strings from reaching the vulnerable code paths, though this approach is considered a temporary workaround rather than a permanent fix. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and can be mapped to ATT&CK technique T1059.007 for application layer execution. Additionally, the issue demonstrates characteristics of CWE-787, out-of-bounds write conditions, which occurs when a program writes data past the end of a buffer. System administrators should also consider implementing network segmentation and access controls to limit potential exploitation of this vulnerability, particularly in environments where the UDFclient application is exposed to untrusted network traffic or user inputs.