Debian Security Advisory

DLA-1728-1 openssh -- LTS security update

Date Reported:
25 Mar 2019
Affected Packages:
Security database references:
In the Debian bugtracking system: Bug 793412, Bug 919101, Bug 923486.
In Mitre's CVE dictionary: CVE-2018-20685, CVE-2019-6109, CVE-2019-6111.
More information:

Multiple scp client vulnerabilities have been discovered in OpenSSH, the premier connectivity tool for secure remote shell login and secure file transfer.

  • CVE-2018-20685

    In scp.c, the scp client allowed remote SSH servers to bypass intended access restrictions via the filename of . or an empty filename. The impact was modifying the permissions of the target directory on the client side.

  • CVE-2019-6109

    Due to missing character encoding in the progress display, a malicious server (or Man-in-The-Middle attacker) was able to employ crafted object names to manipulate the client output, e.g., by using ANSI control codes to hide additional files being transferred. This affected refresh_progress_meter() in progressmeter.c.

  • CVE-2019-6111

    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 performed cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server (or Man-in-The-Middle attacker) was able to overwrite arbitrary files in the scp client target directory. If recursive operation (-r) was performed, the server was able to manipulate subdirectories, as well (for example, to overwrite the .ssh/authorized_keys file).

For Debian 8 Jessie, these problems have been fixed in version 1:6.7p1-5+deb8u8.

We recommend that you upgrade your openssh packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: