Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2017-3737

Severity CVSS v4.0:
Pending analysis
Type:
CWE-125 Out-of-bounds Read
Publication date:
07/12/2017
Last modified:
20/04/2025

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.

Impact

Vector 3.x
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x
5.90
Severity 3.x
MEDIUM
Vector 2.0
AV:N/AC:M/Au:N/C:P/I:N/A:N CVSS v2.0 Severity and Metrics:

Base Score: 4.30 MEDIUM
Vector: AV:N/AC:M/Au:N/C:P/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Medium
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): None
Availability (A): None

Base Score 2.0
4.30
Severity 2.0
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:openssl:openssl:1.0.2b:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2c:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2d:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2e:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2f:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2g:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2h:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2i:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2j:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2k:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2l:*:*:*:*:*:*:*
cpe:2.3:a:openssl:openssl:1.0.2m:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools