CVE-2004-1541 in SecureCRT
Summary
by MITRE
SecureCRT 4.0, 4.1, and possibly other versions, allows remote attackers to execute arbitrary commands via a telnet:// URL that uses the /F option to specify a configuration file on a samba share.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability described in CVE-2004-1541 represents a critical command execution flaw in SecureCRT terminal emulation software versions 4.0 and 4.1, with potential impact extending to other versions in the same release series. This vulnerability manifests through the improper handling of telnet:// URLs that utilize the /F option to reference configuration files stored on remote Samba shares. The flaw stems from the application's failure to properly validate and sanitize user-supplied input when processing these specific URL parameters, creating an avenue for remote code execution attacks.
The technical implementation of this vulnerability exploits the way SecureCRT processes command-line arguments and configuration file references. When a user clicks on a malicious telnet:// URL containing the /F parameter pointing to a Samba share, the application attempts to load the specified configuration file without adequate input validation. This lack of proper sanitization allows attackers to inject arbitrary commands that get executed with the privileges of the SecureCRT process, potentially leading to complete system compromise. The vulnerability specifically leverages the /F option which is designed for specifying configuration files, but the implementation fails to properly isolate or validate the file path parameter.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass potential privilege escalation and persistent system compromise. Attackers can leverage this flaw to execute malicious code on target systems, potentially gaining unauthorized access to sensitive data, establishing backdoors, or conducting further reconnaissance activities. The use of Samba shares as the attack vector adds complexity to the exploitation process as it requires the attacker to have access to a Samba server, but this access can be achieved through various means including legitimate network access or social engineering attacks. The vulnerability affects both Windows and Unix-based systems where SecureCRT is installed, making it particularly dangerous in enterprise environments where multiple operating systems coexist.
Security professionals should implement immediate mitigations including restricting user access to potentially malicious URLs, disabling automatic execution of external configuration files, and implementing network-level controls to prevent access to Samba shares from untrusted sources. The vulnerability aligns with CWE-78, which addresses improper neutralization of special elements used in OS commands, and maps to ATT&CK technique T1059.007 for command and script interpreter execution. Organizations should also consider implementing application whitelisting policies to prevent execution of unauthorized code, and regularly update SecureCRT installations to versions that have addressed this vulnerability. Network segmentation and monitoring for suspicious URL access patterns can provide additional layers of defense against exploitation attempts.