CVE-2015-8662 in FFmpeg
Summary
by MITRE
The ff_dwt_decode function in libavcodec/jpeg2000dwt.c in FFmpeg before 2.8.4 does not validate the number of decomposition levels before proceeding with Discrete Wavelet Transform decoding, which allows remote attackers to cause a denial of service (out-of-bounds array access) or possibly have unspecified other impact via crafted JPEG 2000 data.
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Analysis
by VulDB Data Team • 07/01/2022
The vulnerability identified as CVE-2015-8662 represents a critical flaw in the FFmpeg multimedia framework's handling of JPEG 2000 image files. This issue resides within the ff_dwt_decode function located in libavcodec/jpeg2000dwt.c, where the software fails to properly validate the number of decomposition levels specified in maliciously crafted JPEG 2000 data. The absence of input validation creates a scenario where an attacker can manipulate the decomposition level parameter to trigger unexpected behavior in the Discrete Wavelet Transform decoding process. This flaw affects FFmpeg versions prior to 2.8.4, making a significant portion of deployed multimedia processing systems vulnerable to exploitation. The vulnerability specifically targets the JPEG 2000 decoder component, which is widely used in various applications including media players, content management systems, and digital asset processing platforms that rely on FFmpeg for multimedia handling.
The technical implementation of this vulnerability stems from improper bounds checking within the wavelet transform decoding algorithm. When the ff_dwt_decode function processes JPEG 2000 data, it assumes that the number of decomposition levels specified in the file header is valid and within acceptable parameters. However, when an attacker supplies a malformed JPEG 2000 file with an excessive or negative number of decomposition levels, the function proceeds with array indexing operations that exceed allocated memory boundaries. This out-of-bounds memory access can result in segmentation faults that cause application crashes, leading to denial of service conditions for legitimate users. The vulnerability's impact extends beyond simple service disruption, as the improper memory handling may potentially allow for more sophisticated exploitation techniques depending on the execution environment and memory layout. This type of flaw aligns with CWE-129, which describes improper validation of array indices, and represents a classic example of how insufficient input validation can lead to memory corruption vulnerabilities.
The operational impact of CVE-2015-8662 is significant across multiple deployment scenarios where FFmpeg is utilized for multimedia processing. Web applications that accept user-uploaded images, media streaming services, content management systems, and digital asset management platforms all represent potential attack vectors for this vulnerability. An attacker could upload a malicious JPEG 2000 file to any system that processes such media through FFmpeg, causing the application to crash and potentially rendering the service unavailable to legitimate users. The vulnerability's remote exploitability means that attackers do not need physical access to the system, making it particularly dangerous in web-facing applications. Additionally, the unspecified nature of potential other impacts suggests that under certain conditions, this vulnerability might enable more serious consequences including arbitrary code execution, depending on the specific implementation and system configuration. Organizations using FFmpeg in production environments face increased risk of service disruption and potential data availability issues, particularly in scenarios where automated media processing workflows are in place.
Mitigation strategies for CVE-2015-8662 primarily focus on updating FFmpeg installations to version 2.8.4 or later, where the input validation has been properly implemented to prevent invalid decomposition level values from causing memory access violations. System administrators should prioritize patching affected installations and verify that all applications relying on FFmpeg have been updated to secure versions. Network-level protections can include implementing content filtering mechanisms that scan uploaded media files for known malicious patterns, though this approach is less reliable for zero-day exploits. Organizations should also consider implementing proper input sanitization at application layers that use FFmpeg, adding additional validation checks beyond what is provided by the library itself. The ATT&CK framework categorizes this vulnerability under the T1203 - Exploitation for Client Execution tactic, as it involves leveraging software flaws to cause unintended behavior in multimedia processing applications. Security monitoring should include detection of unusual application crashes or memory access patterns that might indicate exploitation attempts, while incident response procedures should account for potential denial of service scenarios that could impact media processing workflows and user experience.