CVE-2021-45764 in GPAC
Summary
by MITRE • 01/14/2022
GPAC v1.1.0 was discovered to contain an invalid memory address dereference via the function shift_chunk_offsets.isra().
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Analysis
by VulDB Data Team • 01/19/2022
The vulnerability identified as CVE-2021-45764 affects GPAC version 1.1.0 and represents a critical memory safety issue that can lead to arbitrary code execution or system instability. This flaw manifests within the shift_chunk_offsets.isra() function, which is part of the GPAC multimedia framework used for processing various media formats including mp4 and other container formats. The issue stems from improper validation of memory addresses during chunk offset manipulation operations, creating a scenario where the application attempts to access memory locations that have not been properly allocated or validated.
The technical root cause of this vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions. When processing multimedia files, the shift_chunk_offsets.isra() function receives input data that may contain malformed or unexpected values in chunk offset fields. The function fails to properly validate these inputs before attempting to dereference memory addresses, allowing attackers to craft specially crafted media files that trigger the invalid memory access. This type of vulnerability falls under the broader category of memory corruption flaws that can be exploited through file-based attacks, particularly in applications that handle untrusted input data.
From an operational perspective, this vulnerability presents significant risks to systems that utilize GPAC for multimedia processing, including content management systems, streaming platforms, and media processing applications. The impact extends beyond simple crashes to potentially enable remote code execution, making it a severe concern for organizations that process user-uploaded media content or integrate GPAC into automated workflows. Attackers can exploit this vulnerability by uploading maliciously crafted media files that, when processed by the vulnerable GPAC version, will trigger the memory access violation and potentially allow for arbitrary code execution on the target system. This aligns with ATT&CK technique T1203 which describes exploitation of software vulnerabilities for privilege escalation and persistent access.
The exploitation of CVE-2021-45764 requires an attacker to construct a media file that contains malformed chunk offset data, which when processed by the affected GPAC version will cause the shift_chunk_offsets.isra() function to attempt accessing invalid memory addresses. The vulnerability is particularly concerning because it can be triggered through normal media processing workflows without requiring special privileges or complex attack vectors. Organizations should consider implementing input validation measures, restricting file type processing, and deploying intrusion detection systems that monitor for unusual memory access patterns. The recommended mitigation strategy involves upgrading to GPAC version 1.1.1 or later where this memory access violation has been addressed through proper input validation and memory address validation procedures. Additionally, organizations should implement sandboxing techniques for media processing and consider using memory protection mechanisms such as address space layout randomization and data execution prevention to reduce the impact of potential exploitation attempts.