CVE-2009-1759 in dTorrent
Summary
by MITRE
Stack-based buffer overflow in the btFiles::BuildFromMI function (trunk/btfiles.cpp) in Enhanced CTorrent (aka dTorrent) 3.3.2 and probably earlier, and CTorrent 1.3.4, allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a Torrent file containing a long path.
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Analysis
by VulDB Data Team • 04/10/2025
The vulnerability identified as CVE-2009-1759 represents a critical stack-based buffer overflow flaw within the Enhanced CTorrent and CTorrent software implementations. This security weakness resides specifically in the btFiles::BuildFromMI function located in the trunk/btfiles.cpp source file, affecting versions 3.3.2 of Enhanced CTorrent and CTorrent 1.3.4, with probable impact on earlier versions. The flaw manifests when these torrent clients process maliciously crafted torrent files containing excessively long path strings, creating a scenario where the application fails to properly validate input length before attempting to store data on the stack.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent stack memory locations. The vulnerability operates through a classic stack corruption mechanism where an attacker crafts a torrent file with an abnormally long path string that exceeds the allocated buffer space within the btFiles::BuildFromMI function. When the torrent client attempts to parse this malformed input, the excessive data overflows the designated stack buffer, potentially overwriting return addresses, function pointers, and other critical stack-based variables that control program execution flow.
From an operational perspective, this vulnerability presents significant risks to both availability and integrity of affected systems. Remote attackers can leverage this flaw to trigger denial of service conditions by causing the torrent client applications to crash and terminate unexpectedly. The impact extends beyond simple service disruption, as the buffer overflow condition creates opportunities for arbitrary code execution, allowing attackers to potentially gain unauthorized control over systems running vulnerable versions of these torrent clients. The attack vector requires only the delivery of a malicious torrent file, making it particularly dangerous in environments where users might unknowingly download content from untrusted sources.
The exploitation of this vulnerability demonstrates characteristics consistent with ATT&CK technique T1203, which involves the use of malicious files to gain initial access or escalate privileges within compromised systems. Network-based attackers can effectively leverage this flaw by distributing malicious torrent files through peer-to-peer networks, web downloads, or other distribution mechanisms. The vulnerability affects both Enhanced CTorrent and CTorrent implementations, indicating a broader impact across similar torrent client software families that may share common code bases or implementation patterns.
Mitigation strategies for this vulnerability should focus on immediate software updates and patches provided by the vendors, as well as network-level controls to prevent the download and execution of untrusted torrent files. System administrators should implement strict input validation measures and consider deploying intrusion prevention systems that can detect and block malformed torrent file content. Additionally, users should be educated about the risks of downloading torrent files from untrusted sources and the importance of maintaining updated software versions to protect against known vulnerabilities. The vulnerability highlights the critical importance of proper bounds checking and input validation in networked applications, particularly those handling untrusted data from external sources.