CVE-2014-4609 in Libav
Summary
by MITRE
Integer overflow in the get_len function in libavutil/lzo.c in Libav before 0.8.13, 9.x before 9.14, and 10.x before 10.2 allows remote attackers to execute arbitrary code via a crafted Literal Run.
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Analysis
by VulDB Data Team • 12/15/2024
The vulnerability identified as CVE-2014-4609 represents a critical integer overflow condition within the libav library's LZO decompression functionality. This flaw exists in the get_len function located in libavutil/lzo.c and affects multiple versions of the Libav multimedia framework including releases before 0.8.13, 9.x before 9.14, and 10.x before 10.2. The vulnerability arises when processing crafted LZO compressed data containing a malicious Literal Run sequence that triggers improper integer arithmetic handling. The integer overflow condition occurs during decompression operations where the library fails to properly validate input data lengths, leading to a situation where a 32-bit integer can exceed its maximum representable value and wrap around to a smaller value. This specific vulnerability is classified under CWE-190 as an Integer Overflow or Wraparound, which is a well-documented weakness in software systems where integer arithmetic operations produce results that exceed the maximum value that can be stored in the designated data type. The flaw enables remote code execution because the overflowed integer value can cause the decompression routine to allocate insufficient memory for the decompressed output or access memory locations outside the intended buffer boundaries. When attackers craft malicious LZO compressed files with carefully constructed Literal Run sequences, they can manipulate the integer overflow to control memory access patterns and potentially execute arbitrary code with the privileges of the process running the affected library. The operational impact of this vulnerability is significant as it allows remote attackers to compromise systems that utilize Libav for multimedia processing, including web servers, media processing applications, and content delivery networks that handle user-provided media files. The attack vector is particularly dangerous because it requires no local privileges and can be exploited through network-based interactions with vulnerable applications. According to ATT&CK framework, this vulnerability maps to T1203 as Exploitation for Client Execution, where attackers leverage software vulnerabilities to execute malicious code remotely. The vulnerability demonstrates a classic example of how decompression routines can become attack surfaces when proper input validation and integer arithmetic bounds checking are not implemented. The memory corruption resulting from this integer overflow can lead to various outcomes including application crashes, denial of service conditions, or more critically, full system compromise through remote code execution. The affected versions of Libav are widely used in multimedia applications, making this vulnerability particularly concerning for organizations maintaining systems that process user-uploaded media content or streaming media data. The root cause lies in inadequate input validation within the decompression logic where the library does not properly check that the calculated output length remains within safe integer bounds before proceeding with memory allocation or data processing operations. This vulnerability highlights the importance of implementing robust input validation and integer overflow protection mechanisms in cryptographic and decompression libraries that handle untrusted data from external sources.
The technical implementation of this vulnerability demonstrates how a seemingly simple arithmetic operation can lead to catastrophic security consequences. The get_len function in libavutil/lzo.c performs calculations to determine the length of data to be decompressed, but fails to validate that these calculations do not result in integer overflow conditions. When an attacker crafts a LZO compressed file with a malicious Literal Run that causes the length calculation to exceed the maximum value representable by a 32-bit signed integer, the overflow occurs and produces a negative or unexpectedly small value. This corrupted length value then propagates through the decompression pipeline, causing memory allocation functions to either allocate insufficient memory for the decompressed data or to attempt to write data beyond the allocated buffer boundaries. The vulnerability specifically affects the LZO decompression algorithm which is commonly used for lossless data compression in various multimedia applications. The integer overflow condition creates a scenario where the decompression routine can be tricked into performing operations on memory locations that are not properly allocated or accessible, leading to potential code execution. The vulnerability is particularly insidious because it can be triggered through normal network-based file processing operations, requiring no special privileges or local access. The exploitability of this vulnerability is enhanced by the fact that many applications that use Libav for multimedia processing are deployed in environments where they process untrusted user input, such as web applications that accept uploaded media files or streaming services that handle user-generated content. The memory corruption resulting from this flaw can manifest in various ways including heap corruption, stack corruption, or control flow hijacking, depending on the specific memory layout and the exact conditions under which the overflow occurs. The vulnerability's impact is amplified by the widespread use of Libav in multimedia processing applications, making it a prime target for attackers seeking to compromise systems that handle multimedia content processing. This vulnerability underscores the critical importance of input validation and integer overflow protection in security-critical libraries, particularly those handling data decompression and cryptographic operations. The flaw serves as a reminder that even well-established multimedia libraries can contain fundamental security issues when proper bounds checking and input validation mechanisms are not implemented. Organizations using affected versions of Libav should prioritize immediate patching and implementation of additional security controls to protect against potential exploitation of this vulnerability. The vulnerability also demonstrates the need for comprehensive testing of decompression routines with malformed inputs to identify potential integer overflow conditions before they can be exploited by malicious actors.