CVE-2004-0418 in CVS
Summary
by MITRE
serve_notify in cvs 1.12.x through 1.12.8 and 1.11.x through 1.11.16 does not properly handle empty data lines which may allow remote attackers to perform an "out-of-bounds" write for a single byte to execute arbitrary code or modify critical program data.
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Analysis
by VulDB Data Team • 05/22/2019
The vulnerability identified as CVE-2004-0418 resides within the concurrent versions system cvs software version 1.12.x through 1.12.8 and 1.11.x through 1.11.16. This flaw manifests in the serve_notify function which processes data lines during communication between client and server components. The vulnerability represents a classic buffer overflow condition that occurs when the software fails to properly validate or handle empty data lines that are transmitted through the network protocol. The issue stems from inadequate bounds checking mechanisms within the data processing routine, allowing maliciously crafted input to bypass normal input validation procedures and trigger memory corruption behaviors.
The technical implementation of this vulnerability involves a specific memory access pattern where the serve_notify function attempts to write data to memory locations without proper boundary verification. When empty data lines are processed, the software's internal buffer management fails to account for these edge cases, leading to an out-of-bounds write operation that affects a single byte. This seemingly minor memory corruption can be exploited by remote attackers to manipulate program execution flow, potentially resulting in arbitrary code execution or modification of critical program data structures. The vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation involves heap memory corruption due to improper data line handling.
The operational impact of this vulnerability extends beyond simple code execution as it provides attackers with potential access to critical system resources and data within the version control environment. Remote exploitation allows attackers to gain unauthorized access to source code repositories and potentially compromise the integrity of the entire software development process. The vulnerability affects organizations that rely on cvs for version control management, particularly those with network-accessible cvs servers. Attackers can leverage this flaw to execute malicious code on the server hosting the cvs repository, potentially gaining persistent access to sensitive source code and development environments. The single-byte out-of-bounds write characteristic makes this vulnerability particularly dangerous as it can be used to manipulate program flow control or corrupt critical data structures without requiring extensive exploitation techniques.
Mitigation strategies for CVE-2004-0418 should prioritize immediate software updates to patched versions of cvs that address the buffer handling issues in the serve_notify function. Organizations should implement network segmentation to limit access to cvs servers and restrict remote access to authorized users only. Additionally, input validation measures should be enhanced to filter out malformed data lines before they reach the vulnerable processing functions. The vulnerability demonstrates the importance of proper memory management and input validation in network services, aligning with ATT&CK technique T1190 for exploitation of remote services. System administrators should also consider implementing intrusion detection systems to monitor for suspicious network traffic patterns that might indicate exploitation attempts, particularly focusing on unusual data line patterns that could trigger the vulnerable code path.