CVE-2021-43572
Published: 09 November 2021
Summary
CVE-2021-43572 is a critical-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Starkbank Ecdsa-Python. Its CVSS base score is 9.8 (Critical).
Operationally, ranked at the 47.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-0251
Vulnerability details
The verify function in the Stark Bank Python ECDSA library (aka starkbank-escada or ecdsa-python) before 2.0.1 fails to check that the signature is non-zero, which allows attackers to forge signatures on arbitrary messages.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requires verification of digital signatures using organization-approved certificates before installation, directly preventing improper verification of cryptographic signatures.
Component authenticity commonly depends on cryptographic signatures; the control enforces proper verification of those signatures.
PKI certificates under an approved policy require cryptographic signature verification on issuance and validation.
Requires cryptographic signatures on authoritative data and support for verifying the chain of trust.
Mandates verification of cryptographic signatures (e.g., DNSSEC RRSIG) on resolution responses, addressing missing or bypassed signature checks.
Integrity tools commonly rely on cryptographic signatures whose improper validation this weakness covers.
Authenticity validation commonly relies on cryptographic signature or certificate checks that this control enforces.