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SSL Death Alert
SSL Death Alert is a denial-of-service vulnerability in OpenSSL TLS/SSL handshake processing. In the affected ssl3_read_bytes code path, undefined plaintext SSL3_AL_WARNING alerts received during a handshake are improperly ignored while processing continues. An unauthenticated remote peer can repeatedly transmit records containing multiple such alerts after ClientHello, forcing excessive repeated processing. Affected releases include OpenSSL 0.9.8, all 1.0.1 releases, 1.0.2 through 1.0.2h, and 1.1.0.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
An attacker can drive an affected TLS server process to sustained or full CPU utilization with comparatively little bandwidth, preventing the service from accepting or serving legitimate client connections. The issue affects availability; no confidentiality or integrity impact is described.
If you can’t patch tonight, do this now.
Apply per-source connection-rate limits at network boundaries to constrain handshake floods. Where supported, use TLS-aware deep packet inspection to reject the malicious plaintext warning-alert traffic. Restrict exposure of vulnerable TLS services to trusted networks until patches can be deployed.
Patch, then assume compromise.
Upgrade OpenSSL to a fixed vendor-supported release. Upstream fixes are available in OpenSSL 1.0.2j and 1.1.0b; supported downstream distributions should install their vendor-provided security updates. Restart every service linked against OpenSSL after updating, or reboot the host, so the patched library is loaded.
1 exploit validated by Mallory's analysis.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
18 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.