Skip to content

aports
aports
Closed
Opened by Alicha CH@alicha
Report abuse New issue

openssh: Multiple vulnerabilities (CVE-2018-20685, CVE-2019-6109, CVE-2019-6111)

CVE-2018-20685: 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. The impact is modifying the permissions of the target directory on the client side.

References:

https://nvd.nist.gov/vuln/detail/CVE-2018-20685
https://marc.info/?l=oss-security&m=154745764812881&w=2

Patch:

https://github.com/openssh/openssh-portable/commit/6010c0303a422a9c5fa8860c061bf7105eb7f8b2

CVE-2019-6109: 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.

References:

https://nvd.nist.gov/vuln/detail/CVE-2019-6109
https://sintonen.fi/advisories/scp-client-multiple-vulnerabilities.txt

Patch:

https://github.com/openssh/openssh-portable/commit/8976f1c4b2721c26e878151f52bdf346dfe2d54c
possibly additionally needed: https://github.com/openssh/openssh-portable/commit/bdc6c63c80b55bcbaa66b5fde31c1cb1d09a41eb

CVE-2019-6111: 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).

References:

https://nvd.nist.gov/vuln/detail/CVE-2019-6111

Patch:

https://github.com/openssh/openssh-portable/commit/391ffc4b9d31fa1f4ad566499fef9176ff8a07dc

(from redmine: issue id 9995, created on 2019-02-20, closed on 2019-03-05)