CVE-2004-2029 in BNBT
Summary
by MITRE
The Util_DecodeHTTPAuth function in BNBT BitTorrent Tracker Beta 7.5 Release 2 and earlier allows remote attackers to cause a denial of service (crash) via a Basic Authorization HTTP request with a "A==" value.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2004-2029 represents a classic denial of service flaw within the BNBT BitTorrent Tracker software ecosystem. This issue specifically targets the Util_DecodeHTTPAuth function which processes HTTP Basic Authentication requests. The vulnerability manifests when the tracker receives a malformed authorization header containing the specific value "A==" which triggers an improper handling mechanism within the software's authentication parsing logic. The affected version BNBT BitTorrent Tracker Beta 7.5 Release 2 and earlier versions contain this flaw that can be exploited by remote attackers without requiring any authentication credentials or privileged access.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP Basic Authentication headers during the tracker's authentication processing phase. When the Util_DecodeHTTPAuth function encounters the "A==" value in the authorization field, it fails to properly validate or handle the input, leading to a crash condition that terminates the tracker service. This represents a buffer overflow or improper input validation issue that falls under the CWE-121 category of buffer overflow conditions, specifically involving stack-based buffer overflows. The flaw essentially allows attackers to send specially crafted HTTP requests that cause the application to execute invalid memory operations, resulting in an abrupt termination of the service.
The operational impact of this vulnerability extends beyond simple service disruption as it can be leveraged by malicious actors to maintain persistent availability issues within BitTorrent networks that rely on the affected tracker. The remote nature of the exploit means that attackers can target vulnerable trackers from anywhere on the internet without needing physical access or network proximity to the affected systems. This vulnerability directly maps to the ATT&CK technique T1499.004 which involves network denial of service attacks. The consequences include complete service unavailability, potential data loss, and disruption of peer-to-peer file sharing operations that depend on the tracker's functionality, affecting thousands of users who rely on the BitTorrent network infrastructure.
Mitigation strategies for this vulnerability should prioritize immediate patching of the affected BNBT BitTorrent Tracker versions to the latest available releases that contain the necessary code fixes for the authentication parsing logic. System administrators should implement network monitoring to detect unusual HTTP request patterns that may indicate exploitation attempts, particularly focusing on authorization header values that match the vulnerable "A==" pattern. Additionally, deploying web application firewalls and implementing proper input validation mechanisms can help prevent malformed requests from reaching the vulnerable function. The remediation process should also include network segmentation to isolate critical tracker services and implement automated monitoring systems that can detect service crashes and automatically restart affected processes to maintain network availability. Organizations should also consider implementing rate limiting and connection throttling mechanisms to prevent exploitation attempts from overwhelming the system resources during attack phases.