CVE-2007-1654 in SSH Library
Summary
by MITRE
Buffer overflow in the Ne7sshSftp::addOpenHandle function in ne7ssh_sftp.cpp in NetSieben SSH Library (ne7ssh) before 1.2.1 allows user-assisted remote SFTP servers to cause a denial of service (crash) or possibly execute arbitrary code via multiple file transfers, related to multiple open file handles in SFTP (1) put and (2) get operations.
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Analysis
by VulDB Data Team • 08/01/2019
The vulnerability identified as CVE-2007-1654 represents a critical buffer overflow flaw within the NetSieben SSH Library's SFTP implementation. This security issue resides in the Ne7sshSftp::addOpenHandle function located in the ne7ssh_sftp.cpp source file, affecting versions prior to 1.2.1 of the library. The flaw specifically manifests during SFTP operations involving multiple file transfers, creating a scenario where malicious remote SFTP servers can exploit the vulnerability through carefully crafted file handle operations.
The technical implementation of this buffer overflow stems from inadequate input validation and memory management within the SFTP handling code. When the library processes multiple open file handles during SFTP put and get operations, the addOpenHandle function fails to properly bounds-check data structures containing file handle information. This deficiency allows attackers to manipulate the SFTP server to send malformed data that exceeds allocated buffer boundaries, resulting in memory corruption. The vulnerability operates under CWE-121, which classifies buffer overflow conditions where insufficient bounds checking leads to memory corruption, and aligns with ATT&CK technique T1203 for legitimate program exploitation.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable remote code execution. When exploited successfully, the buffer overflow can cause the affected application to crash or potentially allow an attacker to execute arbitrary code with the privileges of the affected process. This makes the vulnerability particularly dangerous in environments where the ne7ssh library is used for SFTP client operations, as it could provide attackers with unauthorized access to systems. The vulnerability's user-assisted nature means that exploitation requires some level of cooperation from the target system, but this cooperation is typically minimal and can be achieved through crafted SFTP server responses.
Mitigation strategies for CVE-2007-1654 focus primarily on upgrading to the patched version 1.2.1 or later of the NetSieben SSH Library. Organizations should prioritize updating their systems to eliminate this vulnerability, particularly in environments where SFTP client functionality is actively used. Additionally, network segmentation and access controls should be implemented to limit exposure to potentially malicious SFTP servers. Security monitoring should include detection of unusual SFTP operations that might indicate exploitation attempts, and regular vulnerability assessments should be conducted to identify other potential buffer overflow vulnerabilities within the application stack. The fix implemented in version 1.2.1 addresses the core memory management issue by introducing proper bounds checking and input validation for file handle operations, ensuring that the addOpenHandle function properly validates all input data before processing.