Denial of service in systemd

1) Infinite loop

EUVDB-ID: #VU8961

Risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-15908

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No

Description

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

The vulnerability exists in systemd due to an infinite loop in the dns_packet_read_type_window() function in the 'systemd-resolved' service. A remote attacker can return specially crafted DNS NSEC resource record data to the connected target client system, trigger an infinite loop and cause the target systemd-resolve service to fail to respond.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install update from vendor's website.

Vulnerable software versions

systemd: 223 - 235

CPE2.3

• cpe:2.3:a:freedesktop_org:systemd:223:*:*:*:*:*:*:*
• cpe:2.3:a:freedesktop_org:systemd:224:*:*:*:*:*:*:*
• cpe:2.3:a:freedesktop_org:systemd:225:*:*:*:*:*:*:*

External links

https://launchpadlibrarian.net/341797217/systemd_dns_DOS.pdf

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.