CVE-2022-1012

Public on

Last Modified: UTC

ModerateModerate ImpactWhat does this mean?
DescriptionStatementMitigationAdditional informationCVSS Score DetailsWeakness (CWE)AcknowledgementsFAQ

Description

The Linux kernel's TCP source port generation algorithm in the TCP stack contains a flaw due to the small table perturb size. This flaw allows an attacker to positively distinguish a system among devices with identical hardware and software, which lasts until the device restarts. An attacker can guess the evolution of the internal state used for source port generation. This information is used to infer the TCP traffic patterns of the victim, guessing the number of outgoing TCP connections established in a specific time frame, which can lead to a system fingerprinting.

The Linux kernel's TCP source port generation algorithm in the TCP stack contains a flaw due to the small table perturb size. This flaw allows an attacker to positively distinguish a system among devices with identical hardware and software, which lasts until the device restarts.

An attacker can guess the evolution of the internal state used for source port generation. This information is used to infer the TCP traffic patterns of the victim, guessing the number of outgoing TCP connections established in a specific time frame, which can lead to a system fingerprinting.

Statement

Red Hat Enterprise Linux version 7 (RHEL7) is not affected by this issue. While RHEL7 implements the TCP port randomization algorithm 3 (the Simple Hash-Based Port Selection Algorithm), which knowingly has shortcomings (as per RFC 6056, item 3.3.3), the object of study of this flaw was the TCP port selector algorithm 4, the Double-Hash Port Selection Algorithm, which is not existent in RHEL7. This flaw is ranked as a Moderate impact due to: * Limited exposure of the data in the TCP stack; * The impact of this vulnerability is limited to a system fingerprinting; * The requirements to carry the attack are elevated, requiring monitoring of the data flow.

Red Hat Enterprise Linux version 7 (RHEL7) is not affected by this issue. While RHEL7 implements the TCP port randomization algorithm 3 (the Simple Hash-Based Port Selection Algorithm), which knowingly has shortcomings (as per RFC 6056, item 3.3.3), the object of study of this flaw was the TCP port selector algorithm 4, the Double-Hash Port Selection Algorithm, which is not existent in RHEL7.

This flaw is ranked as a Moderate impact due to:

  • Limited exposure of the data in the TCP stack;
  • The impact of this vulnerability is limited to a system fingerprinting;
  • The requirements to carry the attack are elevated, requiring monitoring of the data flow.

Mitigation

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Additional information

  • Bugzilla 2064604: kernel: Small table perturb size in the TCP source port generation algorithm can lead to information leak
  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
  • FAQ: Frequently asked questions about CVE-2022-1012

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

6.5

8.2

Attack Vector

Network

Network

Attack Complexity

Low

Low

Privileges Required

None

None

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

Low

Low

Integrity Impact

None

None

Availability Impact

Low

High

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

Red Hat CVSS v3 Score Explanation

This flaw may leak information specific to the network information (C:L) and (A:L) will not cause a system reboot. It can produce predictable information about source TCP ports.

This flaw may leak information specific to the network information (C:L) and (A:L) will not cause a system reboot. It can produce predictable information about source TCP ports.

Acknowledgements

Red Hat would like to thank Moshe Kol (Hebrew University) for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our Red Hat Vulnerability Scanner Certification program.

Want to get errata notifications? Sign up here.