Slackware Linux update for openssh

Published: 2016-08-07 | Updated: 2023-03-20

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2016-6210 CVE-2015-8325
CWE-ID	CWE-200 CWE-264
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software Subscribe	Slackware Linux Operating systems & Components / Operating system
Vendor	Slackware

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) User enumeration via covert timing channel

EUVDB-ID: #VU255

Risk: Medium

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:F/RL:O/RC:C]

CVE-ID: CVE-2016-6210

CWE-ID: CWE-200 - Information exposure

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to enumerate users on system.

The vulnerability exists in most systems where the Blowfish algorithm runs faster than SHA256/SHA512. A remote unauthenticated attacker can determine valid usernames by sending a specially crafted request with a large password (approximately 10,000 characters) to the target ssh daemon. On systems where a valid user's password has been hashed with SHA256/SHA512, the response time will be shorter for a non-existent username than for a valid username.

Successful exploitation of this vulnerability may result in disclosure or user logins.

Mitigation

Update the affected package openssh.

Vulnerable software versions

Slackware Linux: 13.0 - 14.2

External links

http://www.slackware.com/security/viewer.php?l=slackware-security&y=2016&m=slackware-security.613746

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.

2) Incorrect handling of environment files

EUVDB-ID: #VU251

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2015-8325

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a local user to execute arbitrary code on the target system.

The vulnerability exists in portable version of OpenSSH. A local user can execute arbitrary code as root by setting specially crafted environment variables to conduct attacks against the 'bin/login' process on systems, where PAM is configured to read user-specified environment variables and 'sshd_config' is set to 'UseLogin=yes'.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.