CVE-2023-52444 – A directory entry corruption vulnerability in t... (How to Fix)

Q: What is the severity of CVE-2023-52444?

CVE-2023-52444 has a CVSS score of 7.8 (HIGH). A directory entry corruption vulnerability in the Linux kernel's F2FS filesystem allows attackers to corrupt directory structures during rename operations with whiteout flags. This affects Linux systems using the F2FS filesystem and can lead to filesystem corruption and potential denial of service.

📋 TL;DR

A directory entry corruption vulnerability in the Linux kernel's F2FS filesystem allows attackers to corrupt directory structures during rename operations with whiteout flags. This affects Linux systems using the F2FS filesystem and can lead to filesystem corruption and potential denial of service.

💻 Affected Systems

Products:

Linux Kernel

Versions: Linux kernel versions with F2FS support before fixes in stable releases (specific versions vary by distribution)

Operating Systems: Linux distributions using F2FS filesystem

Default Config Vulnerable: ✅ No

Notes: Only affects systems using the F2FS (Flash-Friendly File System). Systems using ext4, XFS, or other filesystems are not vulnerable.

📦 What is this software?

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

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Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete filesystem corruption leading to data loss, system crashes, and denial of service requiring filesystem repair or restoration from backups.

🟠

Likely Case

Directory structure corruption causing file access issues, application failures, and potential system instability requiring filesystem repair.

🟢

If Mitigated

Limited impact to specific directories during rename operations, potentially causing localized file access issues.

🌐 Internet-Facing: LOW - Requires local filesystem access and specific rename operations with whiteout flags.

🏢 Internal Only: MEDIUM - Local users or processes with appropriate permissions can trigger the vulnerability, potentially affecting system stability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of specific rename operations with whiteout flags. No known public exploits.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with commits: 02160112e6d45c2610b049df6eb693d7a2e57b46, 2fb4867f4405aea8c0519d7d188207f232a57862, 53edb549565f55ccd0bdf43be3d66ce4c2d48b28, 5624a3c1b1ebc8991318e1cce2aa719542991024, 6f866885e147d33efc497f1095f35b2ee5ec7310

Vendor Advisory: https://git.kernel.org/stable/c/02160112e6d45c2610b049df6eb693d7a2e57b46

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.

🔧 Temporary Workarounds

Avoid F2FS filesystem

linux

Use alternative filesystems like ext4 or XFS instead of F2FS

Restrict renameat2 system call

linux

Use seccomp or other security mechanisms to restrict renameat2 with whiteout flags

🧯 If You Can't Patch

Monitor for filesystem corruption using fsck or filesystem health monitoring tools
Implement strict access controls to limit who can perform rename operations on F2FS filesystems

🔍 How to Verify

Check if Vulnerable:

Check if system uses F2FS: 'mount | grep f2fs' and check kernel version against patched releases

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes the fix commits: 'uname -r' and check with distribution vendor

📡 Detection & Monitoring

Log Indicators:

Kernel logs showing F2FS corruption messages
Filesystem check (fsck) reporting directory corruption
System logs showing rename operations failing

SIEM Query:

source="kernel" AND ("f2fs" AND ("corruption" OR "bad inode" OR "assert"))

📊 Metadata

CVE ID: CVE-2023-52444

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-119

Published: February 22, 2024

Last Updated: November 21, 2024

🔗 References

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🔗 Related Vulnerabilities

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