Eight eMudhra intermediate CA private keys compromised by weak randomness

Security & privacy2026-10-22T17:15:32+00:00 Disclosure · Real-world · Unit 42

The claim

The authors assert that eight eMudhra intermediate CA private keys were generated with insufficient randomness, enabling attackers to derive the keys and issue fraudulent TLS certificates.

Unit 42 · Unit 42 Writeup

Published as: “EMudhra Intermediate CA Certificates Compromised”

So what

Compromised intermediate CA keys enable attackers to forge trusted TLS certificates, creating a risk of widespread man-in-the-middle attacks against any services that trust those CAs.

The five-minute version

The blog reports that eight intermediate CA private keys from eMudhra were generated with insufficient randomness, allowing key derivation. This weakness lets attackers forge TLS certificates and perform MitM attacks against any domains trusting those intermediates. Major browsers and OS vendors have begun revoking or untrusting the affected CAs, and Palo Alto provides mitigation guidance and product features.

What they found 2

Eight intermediate CA private keys were compromised due to insufficient randomness
“Eight intermediate certificate authority (CA) private keys belonging to Indian CA eMudhra Limited were compromised due to a critical cryptographic defect during the certificate generation process.”
The private keys were generated with insufficient randomness, allowing derivation from public certificates
“The private keys in this incident were generated with insufficient randomness, allowing potential attackers to derive the private keys from the public certificates.”

What undercuts it the paper’s own results

The writeup provides no independent proof, data, or demonstration that the private keys can actually be derived from the public certificates.

What’s new here 4

Discovery of a cryptographic defect in eMudhra intermediate CA key generation
Eight intermediate CA private keys compromised, enabling private key derivation
Browser and OS vendors revoking or untrusting the affected intermediates
Palo Alto offers guidance and automated tools for rapid certificate revocation and re-issuance

Artifacts & methods 2

eMudhra intermediate CA certificatessystem
Palo Alto Networks Next-Gen Trust Securitysystem

Topics

certificate authorityprivate key compromiseinsufficient randomnessTLS man-in-the-middlecertificate revocationcertificate transparencyPKI governance

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