CVE-2017-3737 Information

Description

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.

CVSS Vector

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

Reference

http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html http://www.securityfocus.com/bid/102103 http://www.securitytracker.com/id/1039978 https://access.redhat.com/errata/RHSA-2018:0998 https://access.redhat.com/errata/RHSA-2018:2185 https://access.redhat.com/errata/RHSA-2018:2186 https://access.redhat.com/errata/RHSA-2018:2187 https://cert-portal.siemens.com/productcert/pdf/ssa-179516.pdf https://github.com/openssl/openssl/commit/898fb884b706aaeb283de4812340bb0bde8476dc https://security.FreeBSD.org/advisories/FreeBSD-SA-17:12.openssl.asc https://security.gentoo.org/glsa/201712-03 https://security.netapp.com/advisory/ntap-20171208-0001/ https://security.netapp.com/advisory/ntap-20180117-0002/ https://security.netapp.com/advisory/ntap-20180419-0002/ https://www.debian.org/security/2017/dsa-4065 https://www.digitalmunition.me/2017/12/cve-2017-3737-openssl-security-bypass-vulnerability/ https://www.openssl.org/news/secadv/20171207.txt https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html https://www.tenable.com/security/tns-2017-16

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

5.9