Title: OpenSSH SFTP Command Restriction Bypassing Vulnerability
Severity: MODERATE
Description:
OpenSSH is a freely available, open source implementation of the SSH protocol. It is distributed and maintained by the OpenBSD Project.
A problem in the package could allow a user with restricted privileges to gain unintended privileges, and local access. This could also lead to administrative privileges. The problem is in the implementation of the SFTP server included with the package.
A system may be configured to allow access without passwords by remote users. This is done using the authorized_keys2 file with SSH version 2. Access being granted based on known keys may also be restricted in what kind of access is granted.
OpenSSH, by default, permits user access to a system via SFTP if they have a valid user account. In the event the user has an existing authorized_keys2 file, they're granted access to SFTP without a requirement for authentication, provided the user has the private key.
SFTP is not sufficiently access controlled, and is not governed by the same restrictions as other programs within the SSH suite. Therefore, a user gaining access to the private key of a user with restricted privileges on a system could connect via SFTP, and perform such actions as chown, chmod, rm, or upload and overwrite files. This could result in a user gaining unintended local access, and potentially elevated privileges.
Affected Products:
- FreeBSD FreeBSD 4.4.0
- HP Secure OS software for Linux 1.0.0
- OpenBSD OpenBSD 2.9.0
- OpenBSD OpenSSH 2.5.2
- OpenBSD OpenSSH 2.5.2 p2
- OpenBSD OpenSSH 2.9.0
- OpenBSD OpenSSH 2.9.0 p1
- OpenBSD OpenSSH 2.9.0 p2
- RedHat Linux 7.0.0
- RedHat Linux 7.0.0 alpha
- RedHat Linux 7.0.0 i386
- RedHat Linux 7.1.0 alpha
- RedHat Linux 7.1.0 i386
- RedHat Linux 7.1.0 ia64
- RedHat Linux 7.2.0 i386
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