ArchLinux: 201904-11: openssh: multiple issues
Summary
- CVE-2018-20685 (insufficient validation)
In OpenSSH 7.9, scp.c in the scp client allows remote SSH servers to
bypass intended access restrictions via the filename of . or an empty
filename.
- CVE-2019-6109 (content spoofing)
An issue was discovered in OpenSSH 7.9. Due to missing character
encoding in the progress display, a malicious server (or Man-in-The-Middle attacker) can employ crafted object names to manipulate the
client output, e.g., by using ANSI control codes to hide additional
files being transferred. This affects refresh_progress_meter() in
progressmeter.c.
- CVE-2019-6111 (arbitrary file overwrite)
An issue was discovered in OpenSSH 7.9. Due to the scp implementation
being derived from 1983 rcp, the server chooses which files/directories
are sent to the client. However, the scp client only performs cursory
validation of the object name returned (only directory traversal
attacks are prevented). A malicious scp server (or Man-in-The-Middle
attacker) can overwrite arbitrary files in the scp client target
directory. If recursive operation (-r) is performed, the server can
manipulate subdirectories as well (for example, to overwrite the
.ssh/authorized_keys file).
Resolution
Upgrade to 8.0p1-1.
# pacman -Syu "openssh>=8.0p1-1"
The problems have been fixed upstream in version 8.0p1.
References
https://www.openssh.com/txt/release-8.0 ;r2=1.198&f=h https://github.com/openssh/openssh-portable/commit/6010c0303a422a9c5fa8860c061bf7105eb7f8b2 https://sintonen.fi/advisories/scp-client-multiple-vulnerabilities.txt https://github.com/openssh/openssh-portable/commit/8976f1c4b2721c26e878151f52bdf346dfe2d54c https://github.com/openssh/openssh-portable/commit/391ffc4b9d31fa1f4ad566499fef9176ff8a07dc https://security.archlinux.org/CVE-2018-20685 https://security.archlinux.org/CVE-2019-6109 https://security.archlinux.org/CVE-2019-6111
Workaround
None.