#VU50593 Use of insufficiently random values in Nut/Net - CVE-2020-27213

Vulnerability identifier: #VU50593

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-2020-27213

CWE-ID: CWE-330

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Nut/Net
Server applications / Other server solutions

Vendor: ethernut

Description

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

The vulnerability exists due to the ISN generator relies on a highly predictable source (system timer) and has constant increments. A remote attacker can interfere with traffic, spoof the connection and gain access to sensitive information.  

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Nut/Net: 5.1

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External links
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.