CVE-2011-0189 in Mac OS X
Summary
by MITRE
The default configuration of Terminal in Apple Mac OS X 10.6 before 10.6.7 uses SSH protocol version 1 within the New Remote Connection dialog, which might make it easier for man-in-the-middle attackers to spoof SSH servers by leveraging protocol vulnerabilities.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/19/2025
The vulnerability identified as CVE-2011-0189 resides within the default configuration of Terminal application in Apple Mac OS X 10.6 versions prior to 10.6.7. This issue specifically affects the New Remote Connection dialog functionality where the system defaults to using SSH protocol version 1 instead of the more secure SSH protocol version 2. The fundamental flaw lies in the protocol version selection mechanism that fails to prioritize modern cryptographic standards. SSH protocol version 1 contains inherent security weaknesses including vulnerable key exchange mechanisms and encryption algorithms that have been extensively documented and exploited by attackers. This configuration choice creates a significant security gap that directly violates security best practices established by industry standards such as those outlined in CWE-310, which addresses cryptographic weaknesses and improper implementation of security protocols.
The operational impact of this vulnerability extends beyond simple protocol version selection to encompass the broader security posture of macOS systems utilizing Terminal for remote connections. Attackers can exploit this weakness through man-in-the-middle attacks where they intercept and manipulate communication between the client and target server. The vulnerability specifically leverages known weaknesses in SSHv1's encryption and authentication mechanisms, allowing adversaries to potentially impersonate legitimate SSH servers. This creates a dangerous environment where users may unknowingly establish connections with malicious servers that appear legitimate. The attack surface is particularly concerning given that Terminal is a commonly used application for system administration tasks, making it a prime target for exploitation. According to ATT&CK framework, this vulnerability maps to T1566, which covers credential harvesting through man-in-the-middle techniques, and T1071, which addresses application layer protocol usage for communication.
The technical exploitation of this vulnerability requires minimal sophistication but can yield significant consequences for system security. SSHv1's known vulnerabilities include weak hash functions and susceptibility to key exchange attacks that have been documented since the early 2000s. The default configuration essentially disables security controls that would normally be present in SSHv2 implementations, leaving users exposed to attacks that could compromise authentication credentials and enable unauthorized access to remote systems. This weakness becomes particularly dangerous when users establish connections to untrusted networks or servers where network traffic interception is possible. The vulnerability demonstrates poor security by design principles and violates fundamental security configurations that should prioritize cryptographic strength over backward compatibility. Organizations and individual users who rely on Terminal for remote administration are particularly at risk, as the vulnerability affects the core authentication mechanism used for establishing secure connections to remote systems. The remediation process requires updating to Mac OS X 10.6.7 or later versions where SSHv2 is properly configured as the default protocol version, ensuring that the security controls are appropriately implemented and that cryptographic protocols meet current industry standards.