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The vulnerability resides in the VerifyCertificate() function within Icinga 2 when compiled with OpenSSL versions prior to 1.1.0. Due to improper certificate validation logic, the function fails to correctly authenticate certificate requests during renewal processes. An attacker can craft a malicious certificate request that mimics a legitimate renewal for an existing trusted certificate. This exploit leverages flaws in OpenSSL’s older API where certificate chain verification and signature checks are inadequately performed. By sending this crafted request to an Icinga 2 instance with certificate signing enabled, the system incorrectly validates the request as a genuine renewal. Consequently, the attacker obtains a signed certificate that appears valid within the Icinga 2 trust framework. This fraudulent certificate can then be used to impersonate trusted nodes in the monitoring cluster. The attack requires network access to the Icinga 2 API or certificate issuance endpoint. The vulnerability specifically bypasses the intended checks for certificate authenticity and integrity. It exploits the trust model where certificates are used for mutual authentication between nodes. The issue is critical as it allows unauthorized entity impersonation, potentially leading to data manipulation or service disruption. Patches in later versions enforce strict certificate parameter validation and proper OpenSSL API usage.
Platform: Icinga 2
Version: Before 2.12.12/2.13.12/2.14.6
Vulnerability: Certificate verification bypass
Severity: Critical
date: 2025-05-27
Prediction: Patched 2025-05-27
What Undercode Say:
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!/bin/bash
Check Icinga 2 version
icinga2 –version
Verify OpenSSL version linked
ldd $(which icinga2) | grep ssl
Example certificate request simulation (educational)
openssl req -new -key attacker.key -out malicious.csr
How Exploit:
Craft malicious certificate request mimicking renewal; send to Icinga 2 API with OpenSSL <1.1.0; receive valid certificate; impersonate trusted node.
Protection from this CVE
Update Icinga 2 to 2.12.12/2.13.12/2.14.6; ensure OpenSSL >=1.1.0; disable certificate renewal if unused.
Impact:
Unauthorized certificate issuance; node impersonation; monitoring integrity compromise; potential cluster trust breach.
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Sources:
Reported By: nvd.nist.gov
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