CVE-2008-3734 in Ws Ftp Home
Summary
by MITRE
Format string vulnerability in Ipswitch WS_FTP Home 2007.0.0.2 and WS_FTP Professional 2007.1.0.0 allows remote FTP servers to cause a denial of service (application crash) or possibly execute arbitrary code via format string specifiers in a connection greeting (response).
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Analysis
by VulDB Data Team • 11/03/2024
The vulnerability identified as CVE-2008-3734 represents a critical format string flaw affecting Ipswitch WS_FTP Home 2007.0.0.2 and WS_FTP Professional 2007.1.0.0 client applications. This weakness resides in the client software's handling of connection greetings from remote FTP servers, where the application fails to properly validate or sanitize format specifiers contained within server responses. The flaw manifests when the FTP client processes a maliciously crafted greeting message that contains format string directives, leading to unpredictable behavior in the application's string formatting functions. Such vulnerabilities typically occur when user-supplied input is directly passed to functions like printf or sprintf without proper validation, creating opportunities for attackers to manipulate memory layout and execute malicious code.
The technical implementation of this vulnerability stems from improper input validation within the FTP client's connection handshake process. When a remote FTP server responds to a connection attempt with a greeting message containing format specifiers such as %s, %d, or %x, the WS_FTP client processes these without adequate sanitization. This creates a scenario where an attacker-controlled string can be interpreted as format string arguments, potentially leading to stack-based buffer overflows or memory corruption. The vulnerability operates under the Common Weakness Enumeration framework as CWE-134, which specifically addresses the use of untrusted input in format string functions. The attack vector involves a remote FTP server that can be controlled by an adversary, making this a significant threat to users who connect to untrusted or compromised FTP services.
The operational impact of this vulnerability extends beyond simple denial of service conditions to encompass potential remote code execution capabilities. When exploited successfully, the format string vulnerability can cause the WS_FTP client application to crash or behave unpredictably, resulting in a denial of service that prevents legitimate file transfer operations. However, the more severe implications arise when attackers can manipulate the format string to overwrite memory locations, potentially executing arbitrary code with the privileges of the running FTP client process. This threat level aligns with the MITRE ATT&CK framework under the technique T1059.007 for command and scripting interpreter, where attackers may leverage such vulnerabilities to establish persistent access through compromised client applications. The vulnerability affects users who maintain connections to potentially malicious FTP servers, making it particularly dangerous in environments where network security is not properly enforced.
Mitigation strategies for CVE-2008-3734 require immediate action from affected organizations and users. The most effective approach involves updating to patched versions of WS_FTP software, as Ipswitch has released updates addressing this specific vulnerability. In environments where immediate patching is not feasible, network segmentation and firewall rules can be implemented to restrict access to FTP services from untrusted networks. Additionally, administrators should consider disabling unnecessary FTP client features that might expose the application to malicious greeting messages. The implementation of proper input validation and sanitization within the application code serves as a fundamental defense mechanism, ensuring that any format string directives are properly escaped or removed before processing. Organizations should also implement monitoring solutions to detect unusual patterns in FTP client behavior that might indicate exploitation attempts. Security awareness training for users about connecting to untrusted FTP servers can provide an additional layer of defense against social engineering attacks that might leverage this vulnerability.