#VU54775 Use of cryptographically weak pseudo-random number generator (PRNG) in Fortinet FortiMail - CVE-2021-26091

Vulnerability identifier: #VU54775

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-26091

CWE-ID: CWE-338

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Fortinet FortiMail
Server applications / IDS/IPS systems, Firewalls and proxy servers

Vendor: Fortinet, Inc

Description

The vulnerability allows a remote attacker to reset credentials of other users.

The vulnerability exists due to usage of weak pseudo-random number generator in the authenticator of FortiMail Identity Based Encryption service. A remote attacker can infer parts of users authentication tokens and reset their credentials.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Fortinet FortiMail: 6.2.0 - 6.4.4

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External links
https://www.fortiguard.com/psirt/FG-IR-21-031

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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.