Amazon Linux AMI update for openssh

Published: 2015-09-02

Risk	Low
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2015-6563 CVE-2015-6564
CWE-ID	CWE-20 CWE-416
Exploitation vector	Local
Public exploit	Public exploit code for vulnerability #2 is available.
Vulnerable software Subscribe	Amazon Linux AMI Operating systems & Components / Operating system
Vendor	Amazon Web Services

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Input validation error

EUVDB-ID: #VU33998

Risk: Low

CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2015-6563

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a local user to impersonate other users on the system.

The monitor component in sshd in OpenSSH before 7.0 on non-OpenBSD platforms accepts extraneous username data in MONITOR_REQ_PAM_INIT_CTX requests, which allows local users to conduct impersonation attacks by leveraging any SSH login access in conjunction with control of the sshd uid to send a crafted MONITOR_REQ_PWNAM request, related to monitor.c and monitor_wrap.c.

Mitigation

Update the affected packages:

i686:
    pam_ssh_agent_auth-0.9.3-5.8.45.amzn1.i686
    openssh-debuginfo-6.2p2-8.45.amzn1.i686
    openssh-server-6.2p2-8.45.amzn1.i686
    openssh-ldap-6.2p2-8.45.amzn1.i686
    openssh-6.2p2-8.45.amzn1.i686
    openssh-keycat-6.2p2-8.45.amzn1.i686
    openssh-clients-6.2p2-8.45.amzn1.i686

src:
    openssh-6.2p2-8.45.amzn1.src

x86_64:
    pam_ssh_agent_auth-0.9.3-5.8.45.amzn1.x86_64
    openssh-keycat-6.2p2-8.45.amzn1.x86_64
    openssh-server-6.2p2-8.45.amzn1.x86_64
    openssh-debuginfo-6.2p2-8.45.amzn1.x86_64
    openssh-6.2p2-8.45.amzn1.x86_64
    openssh-clients-6.2p2-8.45.amzn1.x86_64
    openssh-ldap-6.2p2-8.45.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2015-592.html

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Use-after free

EUVDB-ID: #VU1482

Risk: Low

CVSSv3.1: 8.2 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2015-6564

CWE-ID: CWE-416 - Use After Free