CVE-2024-49864
Description
A flaw was found in the Linux kernel's rxrpc module. A race condition exists during the setup of a socket and its associated I/O thread. A remote attacker could send a specially crafted User Datagram Protocol (UDP) packet, which might be processed by rxrpc_encap_rcv() before the I/O thread is fully initialized. This could lead to a kernel 'oops', resulting in a system crash and a denial of service.
Mitigation
To mitigate this issue, prevent the `rxrpc` kernel module from loading. This can be achieved by creating a modprobe configuration file.
Create a file named `/etc/modprobe.d/blacklist-rxrpc.conf` with the following content:
blacklist rxrpc
After creating the file, regenerate the initramfs to ensure the blacklist is applied during boot:
bash
drancut --force
# Or for older systems:
mkinitrd -f /boot/initramfs-$(uname -r).img $(uname -r)
A system reboot is required for the changes to take effect. This mitigation may impact functionality that relies on the rxrpc protocol, such as AFS.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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 Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.7 | 4.7 | 7.5 |
| Attack Vector | Local | Local | Network |
| Attack Complexity | High | High | Low |
| Privileges Required | Low | Low | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
When a race condition makes it possible to bypass a resource cleanup routine or trigger multiple initialization routines, it may lead to resource exhaustion.
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Instability
When a race condition allows multiple control flows to access a resource simultaneously, it might lead the product(s) into unexpected states, possibly resulting in a crash.
Confidentiality,Integrity
Technical Impact: Read Files or Directories; Read Application Data
When a race condition is combined with predictable resource names and loose permissions, it may be possible for an attacker to overwrite or access confidential data (CWE-59).
Access Control
Technical Impact: Execute Unauthorized Code or Commands; Gain Privileges or Assume Identity; Bypass Protection Mechanism
This can have security implications when the expected synchronization is in security-critical code, such as recording whether a user is authenticated or modifying important state information that should not be influenced by an outsider.
Frequently Asked Questions
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