CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.2	$0-$5k	0.00

Summaryinfo

A vulnerability categorized as critical has been discovered in cURL and libcURL up to 7.50.0. The affected element is an unknown function of the component TLS Session Resumption Client Certificate Handler. Executing a manipulation can lead to cryptographic issue. This vulnerability appears as CVE-2016-5419. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in cURL and libcURL up to 7.50.0 (Network Utility Software). It has been declared as critical. This vulnerability affects an unknown functionality of the component TLS Session Resumption Client Certificate Handler. The manipulation with an unknown input leads to a cryptographic issue vulnerability. The CWE definition for the vulnerability is CWE-310. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

curl and libcurl before 7.50.1 do not prevent TLS session resumption when the client certificate has changed, which allows remote attackers to bypass intended restrictions by resuming a session.

The advisory summarizes:

This flaw also affects the curl command line tool.

The weakness was presented 08/03/2016 by Eric Rescorla and Ray Satiro as adv_20160803A as confirmed advisory (Website). The advisory is shared for download at curl.haxx.se. The public release was coordinated in cooperation with the vendor. This vulnerability was named CVE-2016-5419 since 06/10/2016. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1600. The advisory points out:

libcurl would attempt to resume a TLS session even if the client certificate had changed. That is unacceptable since a server by specification is allowed to skip the client certificate check on resume, and may instead use the old identity which was established by the previous certificate (or no certificate). libcurl supports by default the use of TLS session id/ticket to resume previous TLS sessions to speed up subsequent TLS handshakes. They are used when for any reason an existing TLS connection couldn't be kept alive to make the next handshake faster.

The vulnerability was handled as a non-public zero-day exploit for at least 124 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 92742 (FreeBSD : Vulnerabilities in Curl (e4bc70fc-5a2f-11e6-a1bc-589cfc0654e1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family FreeBSD Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 350869 (Amazon Linux Security Advisory for curl: ALAS-2016-730).

Upgrading to version 7.50.1 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (92742), SecurityFocus (BID 92292†) and SecurityTracker (ID 1036538†). See VDB-90449, VDB-90450, VDB-94363 and VDB-95213 for similar entries. Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Network Utility Software

Name

• cURL
• libcURL

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20
• 7.21
• 7.22
• 7.23
• 7.24
• 7.25
• 7.26
• 7.27
• 7.28
• 7.29
• 7.30
• 7.31
• 7.32
• 7.33
• 7.34
• 7.35
• 7.36
• 7.37
• 7.38
• 7.39
• 7.40
• 7.41
• 7.42
• 7.43
• 7.44
• 7.45
• 7.46
• 7.47
• 7.48
• 7.49
• 7.50.0

License

• open-source

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.5
VulDB Meta Temp Score: 7.3

VulDB Base Score: 7.5
VulDB Temp Score: 7.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Cryptographic issue
CWE: CWE-310
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 92742
Nessus Name: FreeBSD : Vulnerabilities in Curl (e4bc70fc-5a2f-11e6-a1bc-589cfc0654e1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: alas-2016-730
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: cURL/libcURL 7.50.1

Timelineinfo

04/01/2016 🔍
06/10/2016 +70 days 🔍
08/03/2016 +54 days 🔍
08/03/2016 +0 days 🔍
08/03/2016 +0 days 🔍
08/04/2016 +1 days 🔍
08/04/2016 +0 days 🔍
08/05/2016 +1 days 🔍
08/10/2016 +5 days 🔍
03/17/2019 +949 days 🔍

Sourcesinfo

Advisory: adv_20160803A
Researcher: Eric Rescorla, Ray Satiro
Status: Confirmed
Confirmation: 🔍
Coordinated: 🔍

CVE: CVE-2016-5419 (🔍)
GCVE (CVE): GCVE-0-2016-5419
GCVE (VulDB): GCVE-100-90448

OVAL: 🔍

SecurityFocus: 92292 - cURL/libcURL CVE-2016-5419 Remote Security Bypass Vulnerability
SecurityTracker: 1036538

See also: 🔍

Entryinfo

Created: 08/04/2016 12:47
Updated: 03/17/2019 21:26
Changes: 08/04/2016 12:47 (67), 03/17/2019 21:26 (25)
Complete: 🔍
Cache ID: 216:190:103

Discussion

Do you need the next level of professionalism?

Upgrade your account now!