Ubuntu update for OpenSSH



Published: 2018-11-06 | Updated: 2023-03-09
Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2016-10708
CVE-2018-15473
CWE-ID CWE-476
CWE-388
Exploitation vector Network
Public exploit Public exploit code for vulnerability #2 is available.
Vulnerable software
Subscribe 		openssh (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Null pointer dereference

EUVDB-ID: #VU14163

Risk: Low

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2016-10708

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The vulnerability exists due to improper processing of out-of-sequence NEWKEYS messages, as defined in the kex.c and packet.c source code files. A remote attacker can send an out-of-sequence NEWKEYS message, trigger a NULL pointer dereference condition and cause the sshd daemon to crash.

Mitigation

Update the affected packages.

Vulnerable software versions

openssh (Ubuntu package): 1:6.6p1-2ubuntu2.2 - 1:7.2p2-4ubuntu2.5

External links

http://usn.ubuntu.com/3809-1/


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.

2) User enumeration

EUVDB-ID: #VU14440

Risk: Medium

CVSSv3.1: 5.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N/E:F/RL:O/RC:C]

CVE-ID: CVE-2018-15473

CWE-ID: CWE-388 - Error Handling

Exploit availability: Yes

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.

Mitigation

Update the affected packages.

Vulnerable software versions

openssh (Ubuntu package): 1:6.6p1-2ubuntu2.2 - 1:7.2p2-4ubuntu2.5

External links

http://usn.ubuntu.com/3809-1/


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.



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