EMudhra Intermediate CA Certificates Compromised

What it is

Unit 42 advisory on eight intermediate CA private keys belonging to eMudhra Limited, an Indian CA. The keys were generated with insufficient randomness, so the private keys can be derived from the public certificates. Anyone who derives one can sign TLS certificates for any domain and use them for man-in-the-middle interception, impersonation or session hijacking. eMudhra has revoked the eight certificates, and major browser and OS vendors have revoked or untrusted the intermediates. The page was updated on 26 October 2026.

Preconditions / Affected

• Any certificate in your estate that chains to one of the eight eMudhra intermediates.
• Any client or server whose trust store still contains the affected intermediates and does not check revocation.
• Custom or bundled trust stores, which do not pick up vendor distrust automatically. The advisory names these locations: Linux /etc/ssl/certs, Java keystores, Python certifi bundles, Docker base images and mobile application bundles.
• Hard-coded trust anchors in applications, API clients, containers and deployment scripts.

What to do

1. Inventory public-facing services, web apps, API endpoints, VPN gateways and internal infrastructure, and find certificates that chain to eMudhra intermediates.
2. Search code repositories and build pipelines for bundled eMudhra intermediates or pinned anchors, and search the trust stores listed above.
3. Revoke and reissue any affected certificate through a different, fully trusted CA.
4. Push updated trust stores through MDM to endpoints, servers and container images, explicitly distrusting the affected intermediates.
5. Make web proxies, API gateways and egress controls enforce CRL and OCSP checks strictly, and block connections that present revoked chains.
6. Hunt in logs: - Proxy, network and DNS logs for connections to unknown external IPs using eMudhra-signed certificates. - Telemetry for spikes in TLS handshake failures, certificate validation errors or untrusted-issuer warnings, which may indicate MitM or proxy insertion. - Authentication logs for SSO, VPN and cloud portals around the compromise window, to check that sessions were not intercepted or replayed via rogue certificates.
7. Longer term, monitor public CT logs (crt.sh or an automated monitor) for unauthorized certificates on your domains, set DNS CAA records to limit which CAs may issue for you, and move to automated certificate lifecycle management with short-lived certificates.

Caveats

• The page gives no certificate fingerprints, serial numbers or subject names for the eight intermediates, and no compromise date or window. The hunting step about "the time frame of the compromise" cannot be scoped from this page alone. The linked Bugzilla bug 2083449 and the Google Security post "Compromised eMudhra Intermediate CA Certificates" are the likely sources for those identifiers.
• It does not describe the randomness flaw beyond "insufficient randomness", and it reports no observed exploitation.
• The product sections (Next-Gen Trust Security, Prisma Browser, Unit 42 services) are vendor material. The Prisma Browser note refers to extension-based attacks, which this incident does not involve.