CVE-2011-1595 in rdesktop
Summary
by MITRE
Directory traversal vulnerability in the disk_create function in disk.c in rdesktop before 1.7.0, when disk redirection is enabled, allows remote RDP servers to read or overwrite arbitrary files via a .. (dot dot) in a pathname.
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Analysis
by VulDB Data Team • 08/04/2024
The vulnerability identified as CVE-2011-1595 represents a critical directory traversal flaw in the rdesktop remote desktop protocol client software. This vulnerability specifically affects versions prior to 1.7.0 and manifests within the disk_create function located in the disk.c source file. The flaw becomes exploitable when disk redirection functionality is enabled in the rdesktop client, creating a significant security risk for users who connect to remote RDP servers that may be compromised or malicious in nature.
The technical exploitation of this vulnerability occurs through the manipulation of pathname strings using the .. (dot dot) sequence, which is a classic directory traversal technique. When a remote RDP server enables disk redirection and sends malicious file path requests to the vulnerable rdesktop client, the client fails to properly sanitize or validate the input paths. This allows attackers to navigate outside the intended directory boundaries and access arbitrary files on the local system or overwrite critical system files. The vulnerability stems from inadequate input validation and path resolution logic within the disk redirection implementation, which does not properly handle relative path components that could lead to unauthorized system access.
The operational impact of this vulnerability extends beyond simple information disclosure to include potential system compromise and persistent access. Attackers who successfully exploit this flaw can read sensitive files such as configuration data, user credentials, or system binaries, potentially leading to privilege escalation or complete system takeover. The vulnerability is particularly dangerous in enterprise environments where remote desktop connections are frequently used, as it can enable attackers to gain unauthorized access to internal systems through compromised RDP servers. This type of attack aligns with the attack technique described in the MITRE ATT&CK framework under T1071.004 for application layer protocol usage and T1059.001 for command and scripting interpreter.
The root cause of this vulnerability can be categorized as a CWE-22 weakness, specifically "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')", which is a well-documented security flaw that has plagued numerous software applications. The vulnerability demonstrates poor input validation practices and inadequate boundary checking within the file system access control mechanisms. Organizations using rdesktop versions prior to 1.7.0 face significant risk exposure, particularly when connecting to untrusted or potentially malicious RDP servers. The vulnerability affects both read and write operations, meaning attackers can not only extract sensitive data but also modify or corrupt system files, potentially leading to persistent backdoors or system instability. Security professionals should consider this vulnerability as part of their broader assessment of remote desktop security posture, especially when evaluating the risks associated with disk redirection features that are often enabled for legitimate business purposes.
Mitigation strategies for CVE-2011-1595 include immediate patching to rdesktop version 1.7.0 or later, which contains the necessary fixes for the directory traversal vulnerability. Organizations should also implement network segmentation and access controls to limit RDP server access to trusted networks and users only. Additional protective measures include disabling disk redirection when it is not required, implementing network monitoring to detect unusual file access patterns, and conducting regular security assessments of remote desktop configurations. The vulnerability highlights the importance of input validation and proper path handling in client-side applications, particularly those that interact with file systems or network resources. Security teams should also consider implementing security awareness training for administrators who manage remote desktop environments, emphasizing the risks associated with enabling potentially dangerous features like disk redirection without proper security controls in place.