Apple Mac OS X 10.9.2 OpenSSL Trust Evaluation Agent SSL_CTX_set_verify input validation

CVSS Meta Temp Score
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CTI Interest Score
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5.9$0-$5k0.00

Summaryinfo

A vulnerability was found in Apple Mac OS X 10.9.2. It has been rated as critical. This affects the function SSL_CTX_set_verify of the component OpenSSL Trust Evaluation Agent. The manipulation leads to input validation. This vulnerability is traded as CVE-2014-2234. Furthermore, there is an exploit available. It is suggested to update the configuration settings.

Detailsinfo

A vulnerability was found in Apple Mac OS X 10.9.2 (Operating System). It has been rated as critical. This issue affects the function SSL_CTX_set_verify of the component OpenSSL Trust Evaluation Agent. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, and integrity. The summary by CVE is:

A certain Apple patch for OpenSSL in Apple OS X 10.9.2 and earlier uses a Trust Evaluation Agent (TEA) feature without terminating certain TLS/SSL handshakes as specified in the SSL_CTX_set_verify callback function s documentation, which allows remote attackers to bypass extra verification within a custom application via a crafted certificate chain that is acceptable to TEA but not acceptable to that application.

The weakness was shared 03/03/2014 by Hynek Schlawack as Apple OpenSSL Verification Surprises as not defined advisory (Blog). The advisory is shared at hynek.me. The identification of this vulnerability is CVE-2014-2234 since 02/28/2014. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details as well as a public exploit are known. The advisory points out:

As for the return code of this callback, Apple’s own documentation says: "The return value of verify_callback controls the strategy of the further verification process. If verify_callback returns 0, the verification process is immediately stopped with “verification failed” state. If SSL_VERIFY_PEER is set, a verification failure alert is sent to the peer and the TLS/SSL handshake is terminated." (…) But that’s not the case.

A public exploit has been developed by Hynek Schlawack in ANSI C and been published immediately after the advisory. The exploit is available at hynek.me. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $5k-$25k.

It is possible to mitigate the problem by applying the configuration setting Disable TEA. A possible mitigation has been published immediately after the disclosure of the vulnerability. The advisory contains the following remark:

In their response to my bug report, Apple suggested to use a self-compiled OpenSSL (…until I’m ready to migrate to their SecureTransport). Generally that’s good advice because their OpenSSL is hopelessly out of date.

The vulnerability is also documented in the databases at X-Force (91612), SecurityFocus (BID 65989†) and Vulnerability Center (SBV-43929†). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.5
VulDB Meta Temp Score: 5.9

VulDB Base Score: 6.5
VulDB Temp Score: 5.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: Hynek Schlawack
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Config
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
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Exploit Delay Time: 🔍

Config: Disable TEA

Timelineinfo

02/28/2014 🔍
03/03/2014 +3 days 🔍
03/03/2014 +0 days 🔍
03/03/2014 +0 days 🔍
03/03/2014 +0 days 🔍
03/05/2014 +2 days 🔍
03/05/2014 +0 days 🔍
03/10/2014 +5 days 🔍
04/08/2014 +29 days 🔍
05/24/2017 +1142 days 🔍

Sourcesinfo

Vendor: apple.com

Advisory: Apple OpenSSL Verification Surprises
Researcher: Hynek Schlawack
Status: Not defined

CVE: CVE-2014-2234 (🔍)
GCVE (CVE): GCVE-0-2014-2234
GCVE (VulDB): GCVE-100-12509
X-Force: 91612 - Apple Mac OS X OpenSSL Trust Evaluation Agent security bypass, Medium Risk
SecurityFocus: 65989 - Apple Mac OS X OpenSSL Certificate Validation CVE-2014-2234 Security-Bypass Vulnerability
Vulnerability Center: 43929 - Apple Mac OS X 10.9.2 Remote Security Bypass in OpenSSL Trust Evaluation Agent (TEA), Medium

scip Labs: https://www.scip.ch/en/?labs.20150108

Entryinfo

Created: 03/10/2014 10:59
Updated: 05/24/2017 11:32
Changes: 03/10/2014 10:59 (55), 05/24/2017 11:32 (23)
Complete: 🔍
Cache ID: 216:2F3:103

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