| Summary: | <net-misc/openssh-7.3_p1: User enumeration via covert timing channel | ||
|---|---|---|---|
| Product: | Gentoo Security | Reporter: | Agostino Sarubbo <ago> |
| Component: | Vulnerabilities | Assignee: | Gentoo Security <security> |
| Status: | RESOLVED FIXED | ||
| Severity: | minor | CC: | base-system |
| Priority: | Normal | ||
| Version: | unspecified | ||
| Hardware: | All | ||
| OS: | Linux | ||
| URL: | https://bugzilla.redhat.com/show_bug.cgi?id=1357442 | ||
| Whiteboard: | A4 [glsa glsa blocked cve] | ||
| Package list: | Runtime testing required: | --- | |
| Bug Depends on: | 590202 | ||
| Bug Blocks: | |||
This issue was resolved and addressed in GLSA 201612-18 at https://security.gentoo.org/glsa/201612-18 by GLSA coordinator Aaron Bauman (b-man). |
From ${URL} : When SSHD tries to authenticate a non-existing user, it will pick up a fake password structure hardcoded in the SSHD source code. On this hard coded password structure the password hash is based on BLOWFISH ($2) algorithm. If real users passwords are hashed using SHA256/SHA512, then sending large passwords (10KB) will result in shorter response time from the server for non-existing users. This allows remote attacker to enumerate existing users on system logging via SSHD. Published in: http://seclists.org/fulldisclosure/2016/Jul/51 @maintainer(s): after the bump, in case we need to stabilize the package, please let us know if it is ready for the stabilization or not.