Vulnerability identifier: #VU34848

Vulnerability risk: Medium

CVSSv3.1: 5.7 [AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2015-7851

CWE-ID: CWE-22

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ntp
Server applications / Other server solutions

Vendor: ntp.org

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to input validation error when processing directory traversal sequences in the save_config function in ntpd in ntp_control.c in NTP before 4.2.8p4, when used on systems that do not use '' or '/' characters for directory separation such as OpenVMS,. A remote authenticated attacker can send a specially crafted HTTP request and remote authenticated users to overwrite arbitrary files.

Mitigation
Update to version 4.3.77.

Vulnerable software versions

ntp: 4.3.0 - 4.3.76

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External links
http://support.ntp.org/bin/view/Main/NtpBug2918
http://support.ntp.org/bin/view/Main/SecurityNotice
http://www.talosintel.com/reports/TALOS-2015-0062/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.