CVE-2017-11665 in FFmpeg
Summary
by MITRE
The ff_amf_get_field_value function in libavformat/rtmppkt.c in FFmpeg 3.3.2 allows remote RTMP servers to cause a denial of service (Segmentation Violation and application crash) via a crafted stream.
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Analysis
by VulDB Data Team • 12/14/2022
The vulnerability identified as CVE-2017-11665 resides within the FFmpeg media processing library, specifically in the ff_amf_get_field_value function located in libavformat/rtmppkt.c. This flaw represents a critical security issue that affects version 3.3.2 of the FFmpeg software, which is widely used for handling multimedia content across numerous applications and platforms. The vulnerability manifests when processing RTMP (Real-Time Messaging Protocol) streams, a common protocol for streaming audio, video, and data between Flash clients and servers. The issue stems from inadequate input validation and memory handling within the AMF (Action Message Format) parsing logic that FFmpeg employs when processing RTMP packets.
The technical exploitation of this vulnerability occurs when a remote RTMP server crafts a malicious stream containing specially formatted AMF data. When FFmpeg's ff_amf_get_field_value function attempts to parse this malformed data, it fails to properly validate the input structure, leading to a segmentation fault and subsequent application crash. This behavior constitutes a classic denial of service condition where legitimate users cannot access the media content due to the application crashing. The vulnerability is particularly concerning because RTMP is commonly used in live streaming scenarios, making this attack vector potentially widespread and impactful in real-world deployments.
From an operational perspective, this vulnerability creates significant risks for organizations relying on FFmpeg for media processing, including content delivery networks, streaming platforms, and multimedia applications. The remote nature of the attack means that malicious actors can exploit this flaw without requiring local access to the target system, making it particularly dangerous in networked environments. The impact extends beyond simple service disruption as it can lead to complete application failures, requiring manual intervention to restore services. This vulnerability directly maps to CWE-125: Out-of-bounds Read and CWE-476: NULL Pointer Dereference, indicating memory safety issues that are common in media processing libraries handling untrusted input streams. Organizations using FFmpeg versions prior to the patched release are at risk of experiencing service interruptions, potential data loss, and increased operational overhead due to system recovery efforts.
Mitigation strategies for CVE-2017-11665 primarily involve upgrading to FFmpeg version 3.3.3 or later, which contains the necessary patches to address the memory handling issues in the AMF parsing code. System administrators should also implement network-level protections such as RTMP stream filtering and monitoring to detect and block suspicious traffic patterns. Additionally, organizations should consider implementing sandboxing techniques for media processing components and establishing robust input validation mechanisms to prevent similar vulnerabilities from affecting other parts of their multimedia infrastructure. The ATT&CK framework categorizes this vulnerability under T1499.004: Endpoint Denial of Service, highlighting the importance of defending against resource exhaustion and application stability threats in multimedia processing environments. Regular security assessments and vulnerability scanning should be conducted to identify potential exposure to similar flaws in other media processing libraries and components.