CVE-2013-1968 in Subversion
Summary
by MITRE
Subversion before 1.6.23 and 1.7.x before 1.7.10 allows remote authenticated users to cause a denial of service (FSFS repository corruption) via a newline character in a file name.
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Analysis
by VulDB Data Team • 05/14/2021
The vulnerability identified as CVE-2013-1968 affects the Subversion version control system and represents a significant security flaw that enables authenticated remote attackers to corrupt FSFS repositories through carefully crafted file names containing newline characters. This vulnerability exists in Subversion versions prior to 1.6.23 and 1.7.10, where the system fails to properly validate and sanitize file names during repository operations. The flaw specifically targets the FSFS (File System File System) storage backend which is the default storage mechanism for Subversion repositories, making it particularly dangerous as it directly impacts the integrity of version-controlled data.
The technical implementation of this vulnerability stems from inadequate input validation within Subversion's file name handling routines. When an authenticated user submits a file name containing newline characters, the system processes these characters without proper sanitization, leading to corruption of the underlying filesystem structures. This occurs because the newline characters interfere with the repository's internal data structures and indexing mechanisms, causing the FSFS storage system to misinterpret file boundaries and metadata. The vulnerability operates at the filesystem level where the repository's internal representation becomes inconsistent, potentially leading to complete repository corruption that requires manual intervention and data recovery procedures.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential data loss and repository integrity compromise. Attackers can exploit this weakness to render entire repositories unusable, requiring administrators to restore from backups or manually repair corrupted repository structures. This type of attack can be particularly devastating in environments where version control repositories contain critical application source code, configuration files, or other essential business data. The vulnerability also impacts automated build and deployment systems that rely on Subversion repositories, potentially causing widespread service disruption. From a cybersecurity perspective, this represents a privilege escalation vector that allows authenticated users to cause persistent damage to the version control infrastructure.
Organizations affected by CVE-2013-1968 should implement immediate patching strategies to upgrade to Subversion versions 1.6.23 or 1.7.10 and later, which contain the necessary input validation fixes. System administrators should also consider implementing additional monitoring and access controls around repository operations to detect potential exploitation attempts. The vulnerability aligns with CWE-172, which addresses improper handling of Unicode characters, and maps to ATT&CK technique T1499.004 for data corruption attacks. Organizations should conduct thorough repository audits to identify any existing corruption and establish regular backup procedures to ensure rapid recovery in case of future incidents. Security teams should also review authentication and authorization controls to limit the number of users with write permissions to critical repositories, reducing the attack surface for this type of vulnerability.