Linux Kernel up to 5.1.10 MSS TCP Fragment resource consumption

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Linux Kernel up to 4.4.181/4.9.181/4.14.126/4.19.51/5.1.10. Affected is an unknown function of the component MSS. Such manipulation as part of TCP Fragment leads to resource consumption. This vulnerability is uniquely identified as CVE-2019-11479. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Linux Kernel up to 4.4.181/4.9.181/4.14.126/4.19.51/5.1.10 (Operating System) and classified as problematic. Affected by this issue is an unknown code block of the component MSS. The manipulation as part of a TCP Fragment leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.

The weakness was disclosed 06/19/2019 with Netflix (Website). The advisory is shared for download at support.f5.com. This vulnerability is handled as CVE-2019-11479 since 04/23/2019. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

The commercial vulnerability scanner Qualys is able to test this issue with plugin 237298 (Red Hat Update for kernel (Sad SACK) (RHSA-2019:1483)).

Upgrading to version 4.4.182, 4.9.182, 4.14.127, 4.19.52 or 5.1.11 eliminates this vulnerability. Applying the patch 967c05aee439e6e5d7d805e195b3a20ef5c433d6/5f3e2bf008c2221478101ee72f5cb4654b9fc363 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at SecurityFocus (BID 108818†). The entries VDB-136601, VDB-136651 and VDB-136655 are pretty similar. Once again VulDB remains the best source for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 6.0

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CNA Base Score: 5.3
CNA Vector (Canonical Ltd.): 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Resource consumption
CWE: CWE-400 / CWE-404
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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Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 4.4.182/4.9.182/4.14.127/4.19.52/5.1.11
Patch: 967c05aee439e6e5d7d805e195b3a20ef5c433d6/5f3e2bf008c2221478101ee72f5cb4654b9fc363

Timelineinfo

04/23/2019 🔍
06/17/2019 +55 days 🔍
06/19/2019 +2 days 🔍
06/19/2019 +0 days 🔍
10/06/2023 +1570 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: RHSA-2019:1594
Organization: Netflix
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2019-11479 (🔍)
GCVE (CVE): GCVE-0-2019-11479
GCVE (VulDB): GCVE-100-136652
SecurityFocus: 108818 - Linux Kernel CVE-2019-11479 Denial of Service Vulnerability

See also: 🔍

Entryinfo

Created: 06/19/2019 17:32
Updated: 10/06/2023 12:44
Changes: 06/19/2019 17:32 (65), 06/25/2020 16:20 (4), 10/06/2023 12:38 (5), 10/06/2023 12:44 (12)
Complete: 🔍
Cache ID: 216::103

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