#VU50601 Use of insufficiently random values in Nucleus NET and Nucleus ReadyStart - CVE-2020-28388

Vulnerability identifier: #VU50601

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-28388

CWE-ID: CWE-330

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nucleus NET
Server applications / Other server solutions
Nucleus ReadyStart
Server applications / Other server solutions

Vendor: Siemens

Description

The vulnerability allows a remote attacker to compromise the target system.

The vulnerability exists due to the ISN generator relies on a combination of values that can be inferred from a network capture. A remote attacker can interfere with traffic, spoof the connection and gain access to sensitive information.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Nucleus NET: 4.3

Nucleus ReadyStart: before 2012.12

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External links
https://cert-portal.siemens.com/productcert/pdf/ssa-362164.pdf
https://www.forescout.com/company/blog/numberjack-forescout-research-labs-finds-nine-isn-generation-vulnerabilities-affecting-tcpip-stacks/

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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.