CVE-2016-1897 in FFmpeg
Summary
by MITRE
FFmpeg 2.x allows remote attackers to conduct cross-origin attacks and read arbitrary files by using the concat protocol in an HTTP Live Streaming (HLS) M3U8 file, leading to an external HTTP request in which the URL string contains the first line of a local file.
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Analysis
by VulDB Data Team • 01/27/2025
The vulnerability identified as CVE-2016-1897 represents a critical security flaw in FFmpeg version 2.x that enables remote attackers to execute cross-origin attacks and perform arbitrary file reads through manipulation of the concat protocol within HTTP Live Streaming (HLS) M3U8 files. This vulnerability specifically exploits the way FFmpeg processes media playlists and handles external resource references, creating a pathway for unauthorized data access that extends beyond normal operational boundaries.
The technical implementation of this vulnerability occurs when FFmpeg encounters an HLS M3U8 file that utilizes the concat protocol with a malformed URL string. The flaw manifests when the first line of a local file is embedded within the URL string of an external HTTP request, allowing the media processing engine to inadvertently access and read local system files. This occurs because FFmpeg's handling of the concat protocol does not properly validate or sanitize input parameters before processing them as external resource references, creating a direct pathway for local file inclusion attacks.
From an operational impact perspective, this vulnerability poses significant risks to media processing systems that rely on FFmpeg for content handling and streaming operations. Attackers can leverage this flaw to access sensitive local files including configuration data, user credentials, system logs, and other confidential information stored on the same server hosting the vulnerable media processing infrastructure. The cross-origin nature of the attack means that remote adversaries can exploit this vulnerability without requiring local system access, making it particularly dangerous for web-based media processing services and content delivery networks.
The vulnerability aligns with CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) and CWE-94 (Improper Control of Generation of Code) categories, reflecting the improper handling of file paths and external resource references within the media processing pipeline. Additionally, this flaw maps to ATT&CK technique T1059.007 (Command and Scripting Interpreter: Python) and T1566 (Phishing) when considering how attackers might leverage this vulnerability as part of broader exploitation campaigns targeting media processing systems. The attack chain typically involves crafting malicious M3U8 files with specially formatted concat protocol directives that trigger the vulnerable FFmpeg processing logic.
Mitigation strategies for this vulnerability require immediate patching of FFmpeg installations to versions that address the concat protocol handling flaw, along with implementing strict input validation and sanitization for all HLS playlist processing. Organizations should also deploy network segmentation controls to limit access to media processing systems, implement strict content filtering for M3U8 files, and establish monitoring for unusual external HTTP requests originating from media processing servers. Additionally, deploying web application firewalls and content security policies can help prevent exploitation attempts by blocking malicious URL patterns and restricting cross-origin resource sharing in media processing environments.