OpenSSLFramework / library

CVE-2016-0800

MEDIUM · 5.9 CVSS v3.0 Published 2016-03-01

Mitigation only

No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.

See remediation →

68/100

Remediation priority · Elevated

High EPSS Remotely reachable No privileges Zero-click

Official description

NVD · unedited

The SSLv2 protocol, as used in OpenSSL before 1.0.1s and 1.0.2 before 1.0.2g and other products, requires a server to send a ServerVerify message before establishing that a client possesses certain plaintext RSA data, which makes it easier for remote attackers to decrypt TLS ciphertext data by leveraging a Bleichenbacher RSA padding oracle, aka a "DROWN" attack.

Technical summary

dbcve analysis · high confidence

This is the DROWN attack (Decrypting RSA with Obsolete and Weakened eNcryption). The vulnerability exists in the SSLv2 protocol implementation where servers send a ServerVerify message before properly validating client possession of plaintext RSA data. This timing flaw enables attackers to exploit a Bleichenbacher RSA padding oracle to decrypt TLS ciphertext. The attack leverages the obsolete SSLv2 protocol to break TLS encryption.

MitigationDisable SSLv2 protocol support on all servers and upgrade OpenSSL to version 1.0.1s or 1.0.2g or later to eliminate the vulnerable code path.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

NVD · CPE data

OpenSSLFramework / library

Affected:= 1.0.1= 1.0.1a= 1.0.1b= 1.0.1c= 1.0.1d= 1.0.1e= 1.0.1f= 1.0.1g= 1.0.1h= 1.0.1i= 1.0.1j= 1.0.1k

ClientApplication

Affected:all versions

Steel Belted RadiusApplication

Affected:all versions

CVSS breakdown

From the vector

Attack vector: Network
Complexity: High
Privileges: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: None
Availability: None

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Am I affected?

dbcve checks

Work through these to decide whether this CVE applies to you.

Check OpenSSL version

Run 'openssl version' or check the installed package version

Affected if The installed version is between 1.0.1 and 1.0.1k inclusive (including versions 1.0.1a through 1.0.1k)
Verify SSLv2 is disabled on the server

Attempt an SSLv2 connection using 'openssl s_client -ssl2 -connect <server>:<port>' or scan the server for SSLv2 cipher support

Affected if The server accepts or negotiates an SSLv2 connection, indicating SSLv2 is enabled
Check for SSLv2 in server configuration

Review the server configuration files (e.g., httpd.conf, nginx.conf) for SSLv2 protocol directives or examine the cipher suites offered

Affected if SSLv2 is explicitly listed as enabled or is the default protocol on the server
For Pulsesecure products, inspect SSL/TLS settings

Access the Pulsesecure admin interface or configuration and check which SSL/TLS protocols are enabled

Affected if SSLv2 protocol support is enabled on Pulsesecure Client or Steel Belted Radius (all versions are affected when SSLv2 is on)

You are affected if your server has a vulnerable OpenSSL version (1.0.1 through 1.0.1k) AND SSLv2 protocol is enabled, or if any Pulsesecure product has SSLv2 enabled.

Generated from the published advisory. Verify against your own configuration.

Remediation

From vendor data

Mitigation available No clean upgrade yet — mitigate in the meantime

Mitigation

Disable SSLv2 protocol support on all servers and upgrade OpenSSL to version 1.0.1s or 1.0.2g or later to eliminate the vulnerable code path.

Fix this in OpenSSL Scoped from the published advisory

Consultation6.0 h
Implementation12.0 h
Testing6.0 h
Review / QA4.0 h

28.0 hours of engineering $4,980

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Scan for this in your stack

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-0800 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2016-0800?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsA vendor remedy is published

Severity 5.9 Medium

Exploit likelihood EPSS, next 30 days 82.1%

Affects: OpenSSL

Remediation

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Fix this in OpenSSL 28 hrs · Moderate

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Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

Check your environment

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References