Linux Kernel up to 4.6 net/ipv4/tcp_input.c information disclosure

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

Summaryinfo

A vulnerability identified as critical has been detected in Linux Kernel up to 4.6. This affects an unknown part of the file net/ipv4/tcp_input.c. This manipulation causes information disclosure. This vulnerability is handled as CVE-2016-5696. The attack can be initiated remotely. There is not any exploit available. You should upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 4.6 (Operating System). Affected by this vulnerability is some unknown functionality of the file net/ipv4/tcp_input.c. The manipulation with an unknown input leads to a information disclosure vulnerability. The CWE definition for the vulnerability is CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

net/ipv4/tcp_input.c in the Linux kernel before 4.7 does not properly determine the rate of challenge ACK segments, which makes it easier for man-in-the-middle attackers to hijack TCP sessions via a blind in-window attack.

The bug was discovered 07/11/2016. The weakness was released 08/06/2016 (oss-sec). It is possible to read the advisory at openwall.com. This vulnerability is known as CVE-2016-5696 since 06/16/2016. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1592 according to MITRE ATT&CK.

The vulnerability was handled as a non-public zero-day exploit for at least 26 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 93241 (Ubuntu 16.04 LTS : linux-raspi2 vulnerabilities (USN-3070-2)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157314 (Oracle Enterprise Linux Security Update for kernel (ELSA-2016-2574)-Deprecated).

Upgrading to version 4.7 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published 4 weeks after the disclosure of the vulnerability. Attack attempts may be identified with Snort ID 40063.

The vulnerability is also documented in the databases at Tenable (93241), SecurityFocus (BID 76005†) and SecurityTracker (ID 1036625†). Entries connected to this vulnerability are available at VDB-77497, VDB-79923, VDB-82951 and VDB-82953. Be aware that VulDB is the high quality source for vulnerability data.

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CPE 2.3info

CPE 2.2info

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CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.1
VulDB Meta Temp Score: 5.9

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.8
NVD Vector: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Information disclosure
CWE: CWE-200 / CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 93241
Nessus Name: Ubuntu 16.04 LTS : linux-raspi2 vulnerabilities (USN-3070-2)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: alas-2016-726
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: Kernel 4.7
Patch: git.kernel.org

Snort ID: 40063
Snort Message: OS-LINUX Linux Kernel Challenge ACK provocation attempt
Snort Class: 🔍

Suricata ID: 2023140
Suricata Class: 🔍
Suricata Message: 🔍

Timelineinfo

06/16/2016 🔍
07/11/2016 +25 days 🔍
08/06/2016 +26 days 🔍
08/06/2016 +0 days 🔍
08/08/2016 +2 days 🔍
08/16/2016 +8 days 🔍
08/30/2016 +14 days 🔍
08/31/2016 +1 days 🔍
09/13/2022 +2204 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: USN-3070-2
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2016-5696 (🔍)
GCVE (CVE): GCVE-0-2016-5696
GCVE (VulDB): GCVE-100-90631

OVAL: 🔍

SecurityFocus: 76005
SecurityTracker: 1036625

See also: 🔍

Entryinfo

Created: 08/08/2016 15:22
Updated: 09/13/2022 08:55
Changes: 08/08/2016 15:22 (75), 07/17/2019 20:48 (19), 09/13/2022 08:50 (4), 09/13/2022 08:55 (1)
Complete: 🔍
Cache ID: 216::103

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