CVE-2016-5301 in libtorrent
Summary
by MITRE
The parse_chunk_header function in libtorrent before 1.1.1 allows remote attackers to cause a denial of service (crash) via a crafted (1) HTTP response or possibly a (2) UPnP broadcast.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/27/2024
The vulnerability identified as CVE-2016-5301 affects the libtorrent library version 1.1.0 and earlier, presenting a critical denial of service risk through improper handling of network responses. This flaw exists within the parse_chunk_header function which processes incoming data from network sources, specifically targeting how the library interprets HTTP responses and UPnP broadcasts. The vulnerability demonstrates a classic buffer over-read condition where the function fails to properly validate input data before processing, leading to memory corruption and subsequent application crashes.
The technical exploitation of this vulnerability occurs when a remote attacker crafts malicious HTTP responses or UPnP broadcasts that contain malformed chunk header data. The parse_chunk_header function in libtorrent does not adequately validate the length or structure of chunk headers received from network peers, allowing attackers to send specially crafted data that causes the application to attempt to read beyond allocated memory boundaries. This type of vulnerability aligns with CWE-129, which describes improper validation of length fields, and represents a form of memory safety issue that commonly leads to crash conditions in networked applications. The vulnerability is particularly dangerous because it can be triggered through multiple vectors, including both HTTP protocol interactions and UPnP broadcast communications, expanding the potential attack surface significantly.
From an operational perspective, this vulnerability creates substantial risk for any system utilizing libtorrent versions prior to 1.1.1, particularly in environments where the library processes untrusted network data from multiple sources. The impact extends beyond simple service disruption to potentially compromise the stability of entire torrent clients, media streaming applications, and other software that relies on libtorrent for peer-to-peer file sharing functionality. Attackers can leverage this flaw to repeatedly crash applications, making it a valuable tool for conducting persistent denial of service attacks against vulnerable systems. The vulnerability's presence in widely-used libraries means that numerous applications across different platforms and operating systems may be affected, creating a broad attack surface that security teams must address through immediate patching.
The recommended mitigation strategy involves upgrading to libtorrent version 1.1.1 or later, where the parse_chunk_header function has been properly hardened against malformed input data. Security administrators should also implement network monitoring to detect and block suspicious HTTP responses or UPnP broadcasts that may contain maliciously crafted chunk headers. Additionally, organizations should consider implementing network segmentation and access controls to limit exposure to untrusted network traffic, particularly in environments where libtorrent applications are deployed. This vulnerability demonstrates the importance of proper input validation in network protocols and aligns with ATT&CK technique T1499.004 which covers network disruption through service availability attacks. The incident highlights the critical need for robust memory safety practices in networked applications and serves as a reminder of the potential for seemingly minor parsing flaws to result in significant operational disruptions.