This security bulletin contains one high risk vulnerability.
Exploit availability: YesDescription
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.
Update to version 4.2.7p26.Vulnerable software versions
ntp: 4.2.7, 4.2.7p25CPE2.3
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.