CVE-2022-49014
Description
A flaw was found in the Linux kernel's net: tun module. A use-after-free vulnerability exists in the tun_detach() function. An attacker with administrative (root) privileges could exploit this by causing a network structure to be prematurely released and then accessed, leading to a system crash (denial of service). This vulnerability could potentially be leveraged for arbitrary code execution.
Statement
This issue is considered to be a moderate impact flaw, as the exploitation for this will need an ADMIN (or ROOT) privilege (PR:H) in drivers/net/tun.c.
Mitigation
To mitigate this issue, prevent the `tun` kernel module from loading. This can be achieved by creating a modprobe configuration file.
1. Create or edit `/etc/modprobe.d/blacklist-tun.conf` and add the following line:
blacklist tun2. Rebuild the initial ramdisk:
bash3. Reboot the system for the changes to take effect.
dracut -f -v
Disabling the `tun` module may impact functionality that relies on virtual network interfaces, such as VPN clients or container networking solutions. A system reboot is required for the changes to take effect.
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 | 6.7 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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