Arch Linux Security Advisory ASA-201904-11 ========================================== Severity: High Date : 2019-04-24 CVE-ID : CVE-2018-20685 CVE-2019-6109 CVE-2019-6111 Package : openssh Type : multiple issues Remote : Yes Link : https://security.archlinux.org/AVG-951 Summary ======= The package openssh before version 8.0p1-1 is vulnerable to multiple issues including insufficient validation, arbitrary file overwrite and content spoofing. Resolution ========== Upgrade to 8.0p1-1. # pacman -Syu "openssh>=8.0p1-1" The problems have been fixed upstream in version 8.0p1. Workaround ========== None. Description =========== - 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). Impact ====== A malicious SCP server can overwrite arbitrary files in the scp client target directory. References ========== https://www.openssh.com/txt/release-8.0 https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/scp.c.diff?r1=1.197&r2=1.198&f=h https://github.com/openssh/openssh-portable/commit/6010c0303a422a9c5fa8860c0... https://sintonen.fi/advisories/scp-client-multiple-vulnerabilities.txt https://github.com/openssh/openssh-portable/commit/8976f1c4b2721c26e878151f5... https://github.com/openssh/openssh-portable/commit/391ffc4b9d31fa1f4ad566499... https://security.archlinux.org/CVE-2018-20685 https://security.archlinux.org/CVE-2019-6109 https://security.archlinux.org/CVE-2019-6111