Vulnerability identifier: #VU20371

Vulnerability risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-9153

CWE-ID: CWE-287

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenPGP.js
Universal components / Libraries / Libraries used by multiple products

Vendor: ProtonMail

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due the software does not verify the signature type during verification of a message signature. A remote attacker can send a specially crafted message with replaced signatures with a "standalone" or "timestamp" signature and  forge signed messages.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenPGP.js: 0.1.0 - 4.2.0

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External links
http://github.com/openpgpjs/openpgpjs/pull/797/commits/327d3e5392a6f59a4270569d200c7f7a2bfc4cbc
http://github.com/openpgpjs/openpgpjs/pull/816
http://github.com/openpgpjs/openpgpjs/releases/tag/v4.2.0
http://sec-consult.com/en/blog/advisories/multiple-vulnerabilities-in-openpgp-js/
http://www.bsi.bund.de/SharedDocs/Downloads/EN/BSI/Publications/Studies/Mailvelope_Extensions/Mailv...

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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. However, proof of concept for this vulnerability is available.