CVE-2017-3737
Exploitation likely. EPSS gives it a 79% chance of exploitation in the next 30 days. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an "error state" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
79% chance of exploitation activity in the next 30 days, which ranks it in the 99th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
9 events over 3122 days, from the signal feeds we watch.
- OpenVAS check added
- EPSS band changemoderate → high
- Patch availablerecord updated
- EPSS band changehigh → moderate
- EPSS band changemoderate → high
- Publishedweakness classified, att&ck mapped
Affected products
- MindConnect IoT2040ICS / OT / IoT
- SIMATIC ET 200SP Open Controller CPU 1515SP PCICS / OT / IoT
- MindConnect Nano (IPC227D)ICS / OT / IoT
- SIMATIC HMI WinCC FlexibleICS / OT / IoT
- SIMATIC IPC DiagMonitorICS / OT / IoT
- SIMATIC WinCC OAICS / OT / IoT
- SIMATIC WinCC (TIA Portal)ICS / OT / IoT
- SIMATIC S7-1200ICS / OT / IoT
And 6 more affected products. See all after sign-in
Technical detail
CVSS 3.0 vector
Open in the CVSS calculatorCVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Scored 5.9 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity HighRequires specific conditions like a race condition or non-default configuration
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity NoneNo integrity impact
- Availability NoneNo availability impact
Weaknesses
ATT&CK techniques
Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.
- CollectionT1005Data from Local Systemmedium confidence
- Initial AccessT1190Exploit Public-Facing Applicationhigh confidence
- Privilege EscalationT1068Exploitation for Privilege Escalationhigh confidence
Sources
References in the record
- access.redhat.com/errata/RHSA-2018:2185
- access.redhat.com/errata/RHSA-2018:2186
- github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc
And 29 more references. See all after sign-in
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