#VU64732 Improper Verification of Cryptographic Signature in ecdsa-dotnet - CVE-2021-43569

Vulnerability identifier: #VU64732

Vulnerability 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-2021-43569

CWE-ID: CWE-347

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
ecdsa-dotnet
Universal components / Libraries / Libraries used by multiple products

Vendor: STARK BANK

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to verify function in the Stark Bank .NET ECDSA library (ecdsa-dotnet) fails to check that the signature is non-zero. A remote unauthenticated attacker can forge signatures on arbitrary messages to execute arbitrary code on the target system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

ecdsa-dotnet: 1.3.1

---

External links
https://research.nccgroup.com/2021/11/08/technical-advisory-arbitrary-signature-forgery-in-stark-bank-ecdsa-libraries/
https://github.com/advisories/GHSA-j3jw-j2j8-2wv9

---

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.