CVE-2003-0962 in rsync
Summary
by MITRE
Heap-based buffer overflow in rsync before 2.5.7, when running in server mode, allows remote attackers to execute arbitrary code and possibly escape the chroot jail.
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Analysis
by VulDB Data Team • 07/20/2025
The vulnerability identified as CVE-2003-0962 represents a critical heap-based buffer overflow in rsync versions prior to 2.5.7 when operating in server mode. This flaw exists within the remote synchronization utility that is widely used for data transfer and backup operations across networked systems. The vulnerability specifically affects the server-side implementation of rsync where it processes incoming data from remote clients, creating a potential attack surface that can be exploited by malicious actors.
The technical implementation of this vulnerability stems from improper bounds checking within the rsync server daemon when handling certain data structures during file synchronization operations. Attackers can craft malicious input data that exceeds the allocated buffer space in the heap memory, leading to memory corruption that can be leveraged to overwrite adjacent memory locations. This heap corruption enables attackers to manipulate the program execution flow and potentially execute arbitrary code with the privileges of the rsync server process.
When exploited, this vulnerability can result in significant operational impacts including unauthorized code execution on affected systems, privilege escalation, and potential breakout from chroot jail environments that are typically used to contain server processes. The attack vector requires remote access to the rsync server and can be executed without authentication in many configurations, making it particularly dangerous for systems exposed to untrusted networks. The vulnerability affects systems running rsync versions 2.5.6 and earlier, which were commonly deployed in enterprise environments for backup and synchronization tasks.
The security implications extend beyond simple code execution as the vulnerability can bypass security mechanisms designed to isolate the rsync process within a restricted environment. This capability allows attackers to escape chroot jails and potentially gain access to additional system resources or escalate privileges to root level access. The vulnerability aligns with CWE-121 heap-based buffer overflow category and maps to ATT&CK technique T1059.007 for execution through remote code execution. Organizations using rsync in server mode should prioritize immediate patching of affected systems, as the vulnerability can be exploited by automated scanning tools and represents a significant risk to network security infrastructure.
Mitigation strategies should include immediate deployment of rsync version 2.5.7 or later, which contains the necessary memory bounds checking fixes. Network segmentation and firewall rules should be implemented to restrict access to rsync server ports to trusted networks only. Additionally, system administrators should consider implementing intrusion detection systems to monitor for suspicious rsync traffic patterns and conduct regular vulnerability assessments to identify other potentially affected services or applications within the network infrastructure. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against remote code execution exploits targeting network services.