User enumeration in OpenSSH - CVE-2018-15473
Published: August 17, 2018 / Updated: March 9, 2023
Vulnerability identifier: #VU14440
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:A/U:Green
CVE-ID: CVE-2018-15473
CWE-ID: CWE-388
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: OpenSSH
Affected software:
OpenSSH
OpenSSH
Detailed vulnerability description
The vulnerability allows a remote attacker to enumerate all accounts on the system.
The vulnerability exists due to a logical error in auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c files when processing authentication requests. A remote attacker can send a specially crafted chain of packets and monitor behavior of openssh server to determine presence of a valid username. The server will drop connection upon receiving a malformed authentication packets if the username is valid.
How to mitigate CVE-2018-15473
Update to version 7.8.
You can also install patch from GIT repository: