Vulnerability identifier: #VU52216

Vulnerability risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-25663

CWE-ID: CWE-835

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nucleus NET
Server applications / Other server solutions
Nucleus ReadyStart
Server applications / Other server solutions
Nucleus Source Code
Server applications / Other server solutions
VSTAR
Server applications / Other server solutions
Nucleus 4
Server applications / Other server solutions

Vendor: Siemens

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop when the function that processes IPv6 headers does not check the lengths of extension header options. A remote attacker can consume all available system resources and cause denial of service conditions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nucleus NET: All versions

Nucleus ReadyStart: All versions

Nucleus Source Code: All versions

VSTAR: All versions

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External links
http://ics-cert.us-cert.gov/advisories/icsa-21-103-05
http://cert-portal.siemens.com/productcert/pdf/ssa-248289.pdf

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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.