5 - USN-34-1

Executive Summary

Summary
Title	OpenSSH information leakage

Informations
Name	USN-34-1	First vendor Publication	2004-11-30
Vendor	Ubuntu	Last vendor Modification	2004-11-30
Severity (Vendor)	N/A	Revision	N/A

Security-Database Scoring CVSS v3

Cvss vector : N/A
Overall CVSS Score	NA
Base Score	NA	Environmental Score	NA
impact SubScore	NA	Temporal Score	NA
Exploitabality Sub Score	NA

Calculate full CVSS 3.0 Vectors scores

Security-Database Scoring CVSS v2

Cvss vector : (AV:N/AC:L/Au:N/C:P/I:N/A:N)
Cvss Base Score	5	Attack Range	Network
Cvss Impact Score	2.9	Attack Complexity	Low
Cvss Expoit Score	10	Authentication	None Required
Calculate full CVSS 2.0 Vectors scores

Detail

A security issue affects the following Ubuntu releases:

Ubuntu 4.10 (Warty Warthog)

The following packages are affected:

openssh-server

The problem can be corrected by upgrading the affected package to version 1:3.8.1p1-11ubuntu3.1. In general, a standard system upgrade is sufficient to effect the necessary changes.

Details follow:

@Mediaservice.net discovered two information leaks in the OpenSSH server. When using password authentication, an attacker could test whether a login name exists by measuring the time between failed login attempts, i. e. the time after which the "password:" prompt appears again.

A similar issue affects systems which do not allow root logins over ssh ("PermitRootLogin no"). By measuring the time between login attempts an attacker could check whether a given root password is correct. This allowed determining weak root passwords using a brute force attack.