Cyber Resilience

CVE-2021-44273

HighPublic PoC

Published: 23 December 2021

Published
23 December 2021
Modified
21 November 2024
KEV Added
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Patch
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CVSS Score v3.1 7.4 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0017 37.8th percentile
Risk Priority 15 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-44273 is a high-severity Improper Certificate Validation (CWE-295) vulnerability in E2Bn E2Guardian. Its CVSS base score is 7.4 (High).

Operationally, ranked at the 37.8th 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

Vulnerability details

e2guardian v5.4.x <= v5.4.3r is affected by missing SSL certificate validation in the SSL MITM engine. In standalone mode (i.e., acting as a proxy or a transparent proxy), with SSL MITM enabled, e2guardian, if built with OpenSSL v1.1.x, did not…

more

validate hostnames in certificates of the web servers that it connected to, and thus was itself vulnerable to MITM attacks.

CWE(s)
CWE-295

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

e2bn
e2guardian
5.4.0 — 5.4.3r

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.

SA-19 Component Authenticity
addresses: CWE-295

When certificates are used to establish component provenance, the control requires correct certificate validation procedures.

SC-17 Public Key Infrastructure Certificates
addresses: CWE-295

Mandates approved trust anchors and issuance policies, directly preventing acceptance of unvalidated or untrusted certificates.

SC-45 System Time Synchronization
addresses: CWE-295

Correct system time is required for proper enforcement of certificate notBefore/notAfter dates and time-based revocation checks.

References