NTP BUG 3008: ctl_getitem() return value not always checked

Last update: June 28, 2022 20:06 UTC (57417e17c)

Summary

Resolved 4.2.8p7/ 26 Apr 2016
References Bug 3008 CVE-2016-2519
Affects All ntp-4 releases up to, but not including 4.2.8p7,
and 4.3.0 up to, but not including 4.3.92.		 Resolved in 4.2.8p7.
CVSS2 Score MED 4.9 AV:N/AC:H/Au:S/C:N/I:N/A:C
CVSS3 Score MED 4.2 CVSS:3.0/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:H

Description

ntpq and ntpdc can be used to store and retrieve information in ntpd. It is possible to store a data value that is larger than the size of the buffer that the ctl_getitem() function of ntpd uses to report the return value. If the length of the requested data value returned by ctl_getitem() is too large, the value NULL is returned instead. There are 2 cases where the return value from ctl_getitem() was not directly checked to make sure it’s not NULL, but there are subsequent INSIST() checks that make sure the return value is not NULL. There are no data values ordinarily stored in ntpd that would exceed this buffer length. But if one has permission to store values and one stores a value that is “too large”, then ntpd will abort if an attempt is made to read that oversized value.

Mitigation

Credit

This weakness was discovered by Yihan Lian of the Cloud Security Team, Qihoo 360.

Timeline