CVE-2018-10756 in transmission
Summary
by MITRE
Use-after-free in libtransmission/variant.c in Transmission before 3.00 allows remote attackers to cause a denial of service (crash) or possibly execute arbitrary code via a crafted torrent file.
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Analysis
by VulDB Data Team • 05/16/2020
The vulnerability identified as CVE-2018-10756 represents a critical use-after-free condition within the Transmission BitTorrent client software, specifically in the libtransmission/variant.c component. This flaw exists in versions prior to 3.00 and creates a significant security risk that can be exploited by remote attackers through maliciously crafted torrent files. The vulnerability stems from improper memory management practices where the software attempts to access memory locations that have already been freed, creating a dangerous state that can lead to unpredictable behavior.
The technical implementation of this vulnerability occurs during the parsing of torrent files, where the Transmission client processes the variant data structures that define the torrent metadata. When a specially crafted torrent file is processed, the memory allocation and deallocation sequence becomes corrupted, leading to a use-after-free scenario. This memory corruption can manifest when the software attempts to dereference pointers to memory that has already been released back to the system heap. The flaw is particularly dangerous because it can be triggered remotely without requiring any authentication or local access to the target system, making it an attractive vector for widespread exploitation.
The operational impact of CVE-2018-10756 extends beyond simple denial of service conditions to potentially enable remote code execution. While the primary effect is a crash that causes the Transmission client to terminate unexpectedly, the underlying memory corruption can be leveraged by attackers to inject and execute arbitrary code on the affected system. This represents a severe security risk for users who may unknowingly download and open malicious torrent files, potentially leading to complete system compromise. The vulnerability affects all users running Transmission versions before 3.00, making it a widespread concern across numerous installations.
From a cybersecurity perspective, this vulnerability aligns with CWE-416, which specifically addresses use-after-free conditions in software implementations. The flaw demonstrates poor memory management practices and inadequate input validation during torrent file processing. Security researchers have mapped this vulnerability to ATT&CK technique T1203, which covers exploitation of remote services through crafted inputs, and T1059, representing execution of malicious code through compromised applications. The vulnerability's remote attack surface makes it particularly concerning for organizations that may inadvertently expose Transmission clients to untrusted torrent sources.
Mitigation strategies for CVE-2018-10756 primarily involve immediate upgrading to Transmission version 3.00 or later, which contains the necessary patches to address the memory management issues. Network administrators should implement strict torrent file validation policies and consider deploying network segmentation to limit exposure to potentially malicious content. Additionally, users should exercise caution when downloading torrent files from untrusted sources and maintain current antivirus definitions that can detect malicious torrent files. The vulnerability serves as a reminder of the importance of proper memory management in software development and the critical need for regular security updates to protect against known exploits. Organizations should also consider implementing application whitelisting policies to restrict the execution of unauthorized torrent clients that may be vulnerable to similar memory corruption issues.