Denial of service in Junos OS NTP server

1) Denial of service

EUVDB-ID: #VU4013

Risk: High

CVSSv3.1: 8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2013-5211

CWE-ID: CWE-20 - Improper input validation

Exploit availability: Yes

Description

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

The weakness exists due to an error in the monlist feature in ntp_request.c. By sending a specially crafted REQ_MON_GETLIST or REQ_MON_GETLIST_1 request, a remote attacker can consume available CPU resources and cause the server to crash.

Successful exploitation of the vulnerability results in denial of service on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Juniper Junos OS: 11.4 - 14.1

External links

http://supportportal.juniper.net/s/article/2014-07-Security-Bulletin-Junos-NTP-server-amplification-denial-of-service-attack-CVE-2013-5211

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.