It means that the SSL/TLS certificate presented by the domain failed critical validation checks. This can occur due to missing intermediate certificates, invalid or untrusted Certificate Authorities (CAs), expired chains, or forged certificates. Such conditions severely compromise the authenticity of encrypted communication.
Three questions every analyst asks before acting on this signal.
It means that the SSL/TLS certificate presented by the domain failed critical validation checks. This can occur due to missing intermediate certificates, invalid or untrusted Certificate Authorities (CAs), expired chains, or forged certificates. Such conditions severely compromise the authenticity of encrypted communication.
Because certificate chain failures eliminate the trust model that SSL/TLS relies on. Attackers can exploit these misconfigurations to perform man-in-the-middle attacks, inject malicious content, or impersonate trusted entities. Therefore, this signal warrants immediate investigation.
SOC teams typically flag such events as high-severity alerts. They verify if the failure stems from misconfiguration or malicious activity, correlate it with IP reputation and WHOIS data, and check for repeated occurrences across multiple domains to identify broader infrastructure compromise.
A realistic shape of the entry the engine appends to the risk_signals array when this signal fires. Evidence keys are subgroup-default; per-signal overrides documented in the API reference.
{
"slug": "ssl_cert_auth_critical",
"name": "Critical SSL Certificate Authentication Failure",
"group": "http_crawling_history",
"subgroup": "ssl_behavior",
"direction": "malicious",
"evidence": {
"cert_issued_days_ago": 9,
"issuer": "letsencrypt",
"valid_for_days": 90,
"rotation_count_90d": 3,
"cert_type": "DV"
}
}15 other signals share the same subgroup. They detect related behaviors and often co-fire on the same IOC.
It means the SSL/TLS certificate’s Common Name (CN) or Subject Alternative Name (SAN) does not match the accessed domain…
It means the SSL/TLS certificate of the domain includes verified organizational details that have been authenticated by …
It means the domain is using an SSL/TLS certificate that was generated and signed by the same entity, without verificati…
It means that the SSL/TLS certificate presented by the domain was issued or signed by a Certificate Authority that is no…
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