CVE-2007-5256 in FSD
Summary
by MITRE
Multiple stack-based buffer overflows in FSD 2.052 d9 and earlier, and FSFDT FSD 3.000 d9 and earlier, allow (1) remote attackers to execute arbitrary code via a long HELP command on TCP port 3010 to the sysuser::exechelp function in sysuser.cc and (2) remote authenticated users to execute arbitrary code via long commands on TCP port 6809 to the servinterface::sendmulticast function in servinterface.cc, as demonstrated by a PIcallsign command.
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Analysis
by VulDB Data Team • 10/07/2024
The vulnerability described in CVE-2007-5256 represents a critical stack-based buffer overflow affecting FSD software versions 2.052 d9 and earlier, as well as FSFDT FSD 3.000 d9 and earlier. This vulnerability exists within the communication protocols of these systems, specifically targeting two distinct functions that handle incoming network commands. The flaw allows for remote code execution through carefully crafted input that exceeds the allocated buffer space, potentially enabling attackers to gain complete control over affected systems. The vulnerability impacts both unauthenticated remote attackers who can exploit the issue through TCP port 3010 and authenticated users who can leverage the vulnerability via TCP port 6809, demonstrating the severity and broad attack surface of this flaw.
The technical implementation of this vulnerability stems from inadequate input validation within the sysuser::exechelp function in sysuser.cc and the servinterface::sendmulticast function in servinterface.cc. When processing long HELP commands on TCP port 3010, the system fails to properly bounds-check the input data against the allocated stack buffer, causing a stack overflow condition. Similarly, when handling commands on TCP port 6809, particularly the PIcallsign command, the servinterface::sendmulticast function exhibits the same problematic behavior. These buffer overflows occur because the software does not validate the length of incoming commands before copying them into fixed-size buffers, creating opportunities for attackers to overwrite adjacent stack memory. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is classified under the broader category of CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer, making it a fundamental memory safety issue.
The operational impact of CVE-2007-5256 extends beyond simple system compromise, as it provides attackers with complete remote code execution capabilities that can be leveraged for various malicious activities. An attacker exploiting this vulnerability could execute arbitrary code with the privileges of the affected service, potentially leading to full system compromise, data exfiltration, or establishment of persistent backdoors. The dual attack vector through both TCP ports 3010 and 6809 increases the exploitability of this vulnerability, as it allows for both unauthenticated and authenticated attacks. From an adversary perspective, this vulnerability maps to ATT&CK technique T1059 Command and Scripting Interpreter, specifically targeting the execution of malicious payloads through legitimate system interfaces. The vulnerability also relates to T1210 Exploitation of Remote Services, as it exploits network-facing services to gain unauthorized access.
Mitigation strategies for CVE-2007-5256 should focus on immediate patching of affected systems to address the underlying buffer overflow conditions. Organizations should implement network segmentation to restrict access to TCP ports 3010 and 6809, particularly for systems not requiring these services. Input validation measures should be strengthened across all network interfaces, including implementing proper bounds checking and length validation for all incoming commands. Additionally, system administrators should consider implementing intrusion detection systems to monitor for exploitation attempts and establish network monitoring protocols to detect anomalous command patterns. The vulnerability demonstrates the importance of defensive programming practices and adherence to secure coding standards, particularly in legacy systems that may not have been designed with modern security considerations in mind. Regular security assessments and penetration testing should be conducted to identify similar buffer overflow vulnerabilities in other system components, as this represents a common class of flaws that continues to affect legacy software systems.