CVE-2024-12084

Public on

Last Modified: UTC

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

Description

A heap-based buffer overflow flaw was found in the rsync daemon. This issue is due to improper handling of attacker-controlled checksum lengths (s2length) in the code. When MAX_DIGEST_LEN exceeds the fixed SUM_LENGTH (16 bytes), an attacker can write out of bounds in the sum2 buffer.

Statement

This vulnerability only affects a limited range of Rsync versions, rsync-3.2.7 and rsync-3.3.0. Red Hat Enterprise Linux does not ship these versions of Rsync and is not affected. Red Hat considers the severity of this vulnerability to be Critical only in cases where anonymous read access is allowed. Depending on the configuration and implementation choices, the severity may be significantly reduced for your organization. In all supported versions of Red Hat Enterprise Linux, Rsync is not configured to run as a service by default. There are two different methods for utilizing Rsync from a remote system: contacting an Rsync daemon directly with TCP or using a remote-shell program as the transport (such as ssh or rsh). The risk of this vulnerability changes depending on which connection method is used. The default configuration of an Rsync daemon (rsyncd) running as a service does not require authentication. While rsyncd can be configured to require users to provide valid credentials, anonymous read access is a common configuration used by file sharing and mirroring hosts. The capabilities of the rsyncd process may vary depending on the user configured to run the Rsync daemon. In this scenario, an attacker only requires anonymous read access to a Rsync server in order to trigger this vulnerability. Remote-shell programs provide a layer of defense because they enforce users to have valid credentials while initiating the shell connection. When Rsync is invoked via this method, it spawns as a child of the session and will not remain running indefinitely. Since the process is spawned within the security context of the user, an attacker who is able to exploit this vulnerability remains restricted to the capabilities of the user account used to initiate the session. Authentication and network restrictions significantly reduce the attack surface and restricting permissions for remote shell users is always encouraged to limit the impact of compromised credentials.

Mitigation

Red Hat recommends filtering untrusted connections to Rsync via firewall rules on the host and on network firewall appliances.

Additionally, systems which only need to provide remote Rsync access to users with known identities can enable authentication using the 

auth users
parameter in their rsyncd configuration file (rsyncd.conf).

Systems that provide anonymous read access to hosted files via Rsync, such as mirror hosts, do not have reasonable mitigation options available. We strongly urge operators using vulnerable versions of Rsync to update as soon as possible.

Additional information

  • Bugzilla 2330527: rsync: Heap Buffer Overflow in Rsync due to Improper Checksum Length Handling
  • CWE-122: Heap-based Buffer Overflow

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).

The following CVSS metrics and score provided are preliminary and subject to review.

CVSS v3 Score Breakdown
Red HatNVD

CVSS v3 Base Score

9.8

N/A

Attack Vector

Network

N/A

Attack Complexity

Low

N/A

Privileges Required

None

N/A

User Interaction

None

N/A

Scope

Unchanged

N/A

Confidentiality Impact

High

N/A

Integrity Impact

High

N/A

Availability Impact

High

N/A

CVSS v3 Vector

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

Acknowledgements

Red Hat would like to thank Jasiel Spelman (Google), Pedro Gallegos (Google), and Simon Scannell (Google) 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.
  • The term "Affected" means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.

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.