The decodenetnum function in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to cause a denial of service (assertion failure) via a 6 or mode 7 packet containing a long data value.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-7855 from the MITRE CVE dictionary dictionary and NIST NVD.
This issue did not affect the versions of ntp as shipped with Red Hat Enterprise Linux 5, 6, and 7 as they do not include support for the mrulist feature, which exposes the decodenetnum() function.
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
| Base Score | 3.5 |
|---|---|
| Base Metrics | AV:N/AC:M/Au:S/C:N/I:N/A:P |
| Access Vector | Network |
| Access Complexity | Medium |
| Authentication | Single |
| Confidentiality Impact | None |
| Integrity Impact | None |
| Availability Impact | Partial |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 7 | ntp | Not affected |
| Red Hat Enterprise Linux 6 | ntp | Not affected |
| Red Hat Enterprise Linux 5 | ntp | Not affected |
Vulmon