Use of insufficiently random values in Siemens Nucleus NET and Nucleus ReadyStart

Published: 2021-02-10
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2020-28388
Exploitation vector Network
Public exploit N/A
Vulnerable software
Nucleus NET
Server applications / Other server solutions

Nucleus ReadyStart
Server applications / Other server solutions

Vendor Siemens

Security Advisory

This security advisory describes one medium risk vulnerability.

1) Use of insufficiently random values

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2020-28388

CWE-ID: CWE-330 - Use of Insufficiently Random Values

Exploit availability: No


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.


Install updates from vendor's website.

Vulnerable software versions

Nucleus NET: 4.3

Nucleus ReadyStart: before 2012.12

CPE External links

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.