Title: SCPOnly Multiple Local Vulnerabilities
Severity: HIGH
Description:
The 'scponly' program is a freely available, open-source, restricted secure-copy client. It is available for Unix and Linux operating systems. The tool allows programs such as 'scp', 'rsync', and 'unison' to be executed on a remote computer. A user may transfer files to and from a remote computer without having complete shell access.
The 'scponly' program is prone to multiple local vulnerabilities. These issues can allow local attackers to gain elevated privileges.
The following specific vulnerabilities were identified:
1. A design error affects the 'scponlyc' binary. This issue arises under these conditions:
- 'scponlyc' is installed setuid
- a user-executable dynamically linked setuid binary resides on the same filesystem mount as the user's home directory
- the operating system supports an LD_PRELOAD style mechanism to overload dynamic library loading.
To exploit this issue, a local user may create a hardlink to a setuid root binary in their chroot directory, and then configure LD_PRELOAD to overload a call from the dynamically linked setuid with a malicious function followed by using 'scponlyc' with the malicious chroot directory.
2. If compatibility with 'scp' and 'rsync' has been enabled, an attacker can issue malicious command-line arguments to 'rsync' or 'scp' by combining arguments. This can allow an attacker to bypass security restrictions and to execute arbitrary applications with elevated privileges.
Successful exploitation of these issues can facilitate a complete compromise.
Affected Products:
- Debian Linux 3.1.0
- Debian Linux 3.1.0 alpha
- Debian Linux 3.1.0 amd64
- Debian Linux 3.1.0 arm
- Debian Linux 3.1.0 hppa
- Debian Linux 3.1.0 ia-32
- Debian Linux 3.1.0 ia-64
- Debian Linux 3.1.0 m68k
- Debian Linux 3.1.0 mips
- Debian Linux 3.1.0 mipsel
- Debian Linux 3.1.0 ppc
- Debian Linux 3.1.0 s/390
- Debian Linux 3.1.0 sparc
- Gentoo Linux
- scponly scponly 2.0.0
- scponly scponly 2.1.0
- scponly scponly 2.3.0
- scponly scponly 2.4.0
- scponly scponly 3.0.0
- scponly scponly 3.11.0
- scponly scponly 3.5.0
- scponly scponly 3.8.0
- scponly scponly 3.9.0
- scponly scponly 4.0.0
- scponly scponly 4.1.0
References:
- Sublimation.org: dec 2005 scponly 4.2 release
- Sublimation.org: scponly Homepage
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