Improper Verification of Cryptographic Signature in jsrsasign JavaScript library

1) Improper Verification of Cryptographic Signature

EUVDB-ID: #VU29222

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2020-14968

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

Exploit availability: No

Description

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

The vulnerability exists due to the RSASSA-PSS (RSA-PSS) implementation does not detect signature manipulation/modification by prepending "\0" bytes to a signature. A remote attacker can create multiple valid signatures and prepend these bytes with the goal of triggering memory corruption issues.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

jsrsasign: 0.0.1 - 8.0.16

CPE2.3

• cpe:2.3:a:restaumatic:jsrsasign:0.0.1:*:*:*:*:npm:*:*
• cpe:2.3:a:restaumatic:jsrsasign:0.0.2:*:*:*:*:npm:*:*
• cpe:2.3:a:restaumatic:jsrsasign:0.0.3:*:*:*:*:npm:*:*

External links

https://github.com/kjur/jsrsasign/issues/438
https://github.com/kjur/jsrsasign/releases/tag/8.0.17
https://github.com/kjur/jsrsasign/releases/tag/8.0.18
https://kjur.github.io/jsrsasign/
https://www.npmjs.com/package/jsrsasign

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.