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Self-Signed SSL Certificate Detected

It means the domain is using an SSL/TLS certificate that was generated and signed by the same entity, without verification by a trusted Certificate Authority (CA). Such certificates do not provide authenticity guarantees and are often used in malicious or internal infrastructures.

Analyst Q&A

What this signal answers

The questions every analyst asks before acting on this signal.

What it detects01

What does 'Self-Signed SSL Certificate Detected' mean in SOC or domain analysis?

It means the domain is using an SSL/TLS certificate that was generated and signed by the same entity, without verification by a trusted Certificate Authority (CA). Such certificates do not provide authenticity guarantees and are often used in malicious or internal infrastructures.

Why it matters02

Why is a self-signed SSL certificate a red flag in threat analysis?

Because it allows attackers to deploy encrypted communication channels without passing CA validation checks. This technique is often seen in phishing kits, botnet C2 servers, or fake login portals attempting to mimic legitimate HTTPS behavior.

How analysts use it03

Can legitimate environments also use self-signed certificates?

Yes, in limited contexts such as internal testing, development servers, or private networks. However, on publicly reachable domains, the presence of a self-signed certificate is highly suspicious and should trigger further investigation.

Often paired with:block_domain
Evidence shape

What Self-Signed SSL Certificate Detected looks like in the response

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.

json
{
  "slug": "self_signed_ssl_certificate",
  "name": "Self-Signed SSL Certificate Detected",
  "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"
  }
}
See in API reference
Siblings

Peers in SSL Behavior

14 other signals share the same subgroup. They detect related behaviors and often co-fire on the same IOC.

Critical SSL Certificate Authentication Failure

It means that the SSL/TLS certificate presented by the domain failed critical validation checks. This can occur due to m…

MaliciousCore
Invalid Hostname Validation (CN/SAN Mismatch)

It means the SSL/TLS certificate’s Common Name (CN) or Subject Alternative Name (SAN) does not match the accessed domain…

MaliciousCore
Organization-Validated (OV) SSL Certificate Detected

It means the SSL/TLS certificate of the domain includes verified organizational details that have been authenticated by …

SafeCore
Untrusted Certificate Authority (CA) Detected

It means that the SSL/TLS certificate presented by the domain was issued or signed by a Certificate Authority that is no…

MaliciousCore
Show 10 more in SSL Behavior

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