Vulnerability identifier: #VU52765

Vulnerability risk: High

CVSSv3.1: 7.1 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-21374

CWE-ID: CWE-295

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
nim
Universal components / Libraries / Programming Languages & Components

Vendor: nim-lang.org

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to "nimble refresh" fetches a list of Nimble packages over HTTPS without full verification of the SSL/TLS certificate due to the default setting of httpClient. A remote attacker can perform MitM attack and deliver a modified package list containing malicious software packages

Mitigation
Install updates from vendor's website.

Vulnerable software versions

nim: 1.2.0 - 1.4.2

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External links
http://consensys.net/diligence/vulnerabilities/nim-insecure-ssl-tls-defaults-remote-code-execution/
http://github.com/nim-lang/Nim/pull/16940
http://github.com/nim-lang/nimble/blob/master/changelog.markdown#0130
http://github.com/nim-lang/security/security/advisories/GHSA-c2wm-v66h-xhxx

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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.