CVE-2004-0413 in Subversion
Summary
by MITRE
libsvn_ra_svn in subversion 1.0.4 trusts the length field of (1) svn:// (2) svn+ssh:// and (3) other svn protocol url strings which allows remote attackers to cause a denial of service (memory consumption) and possibly execute arbitrary code via an integer overflow that leads to a heap-based buffer overflow.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/22/2019
The vulnerability described in CVE-2004-0413 represents a critical security flaw in the subversion client library known as libsvn_ra_svn which is part of the Subversion version control system. This issue affects versions including but not limited to 1.0.4 and demonstrates a fundamental flaw in how the library processes network protocol data from svn://, svn+ssh://, and other svn protocol URL strings. The vulnerability arises from the library's blind trust in the length field contained within these protocol communications, creating a dangerous condition where maliciously crafted data can be used to manipulate memory operations.
The technical root cause of this vulnerability lies in the improper validation of length fields within the svn protocol implementation. When the libsvn_ra_svn library receives data from remote svn servers, it directly uses the length field provided in the protocol stream without adequate bounds checking or overflow validation. This allows an attacker to craft a malicious protocol message containing an inflated length value that, when processed, causes an integer overflow condition. The resulting integer overflow subsequently leads to a heap-based buffer overflow, where the library attempts to allocate memory based on the corrupted length value, potentially writing data beyond the intended buffer boundaries.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution. Attackers can leverage this flaw to consume excessive memory resources through the malformed length field, causing system instability and denial of service scenarios. More critically, the heap-based buffer overflow condition creates opportunities for arbitrary code execution, allowing remote attackers to potentially take control of the affected system. This vulnerability affects any system running subversion client software that connects to potentially malicious svn servers, making it particularly dangerous in environments where untrusted repositories are accessed.
The vulnerability maps directly to CWE-121 and CWE-122 within the Common Weakness Enumeration framework, representing heap-based buffer overflow conditions and improper integer handling. From an attack perspective, this flaw aligns with ATT&CK technique T1203, specifically targeting the exploitation of memory corruption vulnerabilities to achieve remote code execution. The attack vector is particularly insidious because it operates at the protocol level, making it difficult to detect through conventional network monitoring and potentially bypassing security controls that focus on application-level threats.
Mitigation strategies for this vulnerability require immediate patching of affected subversion installations to versions that properly validate length fields and implement robust integer overflow protection mechanisms. Organizations should also implement network segmentation to limit access to svn repositories and consider deploying network-based intrusion detection systems that can identify suspicious protocol patterns. Additionally, administrators should ensure that subversion clients only connect to trusted repositories and implement proper access controls to prevent unauthorized modification of svn server configurations that could be used to exploit this vulnerability. The fix typically involves implementing proper input validation, using safe integer arithmetic operations, and ensuring that all buffer allocations are performed with appropriate bounds checking to prevent the exploitation of integer overflow conditions that lead to memory corruption.