Vulnerability identifier: #VU50597

Vulnerability 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]

CVE-ID: CVE-2020-27633

CWE-ID: CWE-330

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
FNET
Server applications / Other server solutions

Vendor: fnet.sourceforge.net

Description

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

The vulnerability exists due to the ISN generator is initialized with a constant value and has constant increments. 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

FNET: 4.6.3

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External links
http://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.