CVE-2012-0814 in SSH
Summary
by MITRE
The auth_parse_options function in auth-options.c in sshd in OpenSSH before 5.7 provides debug messages containing authorized_keys command options, which allows remote authenticated users to obtain potentially sensitive information by reading these messages, as demonstrated by the shared user account required by Gitolite. NOTE: this can cross privilege boundaries because a user account may intentionally have no shell or filesystem access, and therefore may have no supported way to read an authorized_keys file in its own home directory.
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Analysis
by VulDB Data Team • 05/22/2026
The vulnerability described in CVE-2012-0814 represents a critical information disclosure flaw within the OpenSSH implementation that affects versions prior to 5.7. This issue resides in the auth_parse_options function located in the auth-options.c file of the sshd daemon, which processes authentication options during the SSH connection establishment process. The flaw manifests when sshd generates debug messages that inadvertently expose sensitive information contained within authorized_keys command options, creating a potential attack vector for remote authenticated users who can leverage this information to gain unauthorized insights into system configurations and access controls.
The technical implementation of this vulnerability stems from insufficient sanitization of debug output within the authentication parsing logic. When sshd processes command options specified in authorized_keys files, particularly those used for Gitolite implementations where shared user accounts are common, the system logs these options in debug messages without proper obfuscation or filtering. This behavior violates fundamental security principles by exposing configuration details that should remain confidential, particularly when dealing with privileged command options that may reveal system access patterns or administrative configurations. The vulnerability is particularly concerning because it operates at the authentication layer where privilege boundaries are typically enforced, making it possible for users with minimal access rights to gather intelligence about system security controls.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can facilitate more sophisticated attacks by providing attackers with detailed knowledge of system configurations and access patterns. In environments where shared user accounts are employed for Gitolite or similar version control systems, this vulnerability allows attackers to discover command options that may reveal the structure of repository access controls, user permissions, or even administrative commands that could be exploited in subsequent attacks. The cross-privilege boundary nature of this vulnerability is particularly dangerous because it enables users with intentionally restricted shell access or filesystem permissions to obtain information that would normally be restricted to system administrators, effectively undermining the principle of least privilege enforcement.
This vulnerability aligns with CWE-200, which addresses the improper handling of sensitive information, and represents a clear violation of the principle of least privilege as outlined in the MITRE ATT&CK framework under the technique of Credential Access. The flaw demonstrates how seemingly benign debugging functionality can become a security risk when proper information sanitization is not implemented. Organizations using affected OpenSSH versions face significant risk of unauthorized information disclosure, particularly in environments where shared accounts or restricted user access patterns are common. The vulnerability also highlights the importance of secure coding practices in authentication systems, where debug output should never contain sensitive information that could be exploited by authenticated users.
The recommended mitigation strategy involves upgrading to OpenSSH version 5.7 or later, where the debug message generation has been properly modified to prevent exposure of authorized_keys command options. Additionally, system administrators should implement strict logging controls and consider disabling debug output in production environments where such information disclosure risks are present. Organizations should also review their authorized_keys file configurations to minimize the exposure of sensitive command options and implement proper monitoring of authentication logs for unusual activity patterns. The vulnerability underscores the critical importance of thorough security testing of authentication components and the necessity of maintaining current security patches to protect against information disclosure attacks that can compromise system integrity and confidentiality.