CVE-2022-1652: Linux Kernel Use-After-Free Vulnerability

CVE-2022-1652 Overview

CVE-2022-1652 is a use-after-free vulnerability in the Linux Kernel's floppy disk driver, specifically within the bad_flp_intr function. This concurrency flaw allows a local attacker to execute arbitrary code on the system by exploiting a race condition during floppy disk interrupt handling. By executing a specially-crafted program, an attacker could leverage this vulnerability to achieve arbitrary code execution or cause a denial of service condition on affected systems.

Critical Impact

Local attackers with low privileges can exploit this use-after-free vulnerability to execute arbitrary code with elevated privileges or crash the system, potentially compromising the confidentiality, integrity, and availability of affected Linux systems.

Affected Products

• Linux Kernel (multiple versions)
• Red Hat Enterprise Linux 9.0
• Debian Linux 10.0
• NetApp H410C Firmware
• NetApp H300S Firmware
• NetApp H500S Firmware
• NetApp H700S Firmware
• NetApp H410S Firmware

Discovery Timeline

• June 2, 2022 - CVE-2022-1652 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2022-1652

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption flaw that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of CVE-2022-1652, the vulnerability exists in the bad_flp_intr function within the Linux Kernel's floppy disk driver subsystem.

The floppy disk driver handles interrupt requests during disk I/O operations. When an error occurs during these operations, the bad_flp_intr function is invoked to handle the faulty interrupt. Due to improper synchronization in the concurrent execution path, a race condition exists that can lead to memory being accessed after it has been freed.

The attack requires local access to the system and requires low privileges to execute. No user interaction is needed for exploitation, and the scope remains unchanged from the vulnerable component. Successful exploitation can result in complete compromise of system confidentiality, integrity, and availability.

Root Cause

The root cause of this vulnerability lies in inadequate synchronization mechanisms within the floppy disk driver's interrupt handling code. When multiple concurrent operations attempt to access shared memory resources during floppy disk error handling, a race condition emerges. The bad_flp_intr function may reference memory that has already been deallocated by another concurrent operation, resulting in a use-after-free condition.

This type of concurrency bug is particularly dangerous because it can manifest non-deterministically, making it difficult to detect during normal testing but exploitable under specific timing conditions that an attacker can deliberately create.

Attack Vector

The attack vector for CVE-2022-1652 is local, meaning an attacker must have local access to the vulnerable system. The exploitation process involves:

1. The attacker crafts a malicious program designed to trigger the race condition in the floppy disk driver
2. By carefully timing operations that interact with the floppy subsystem, the attacker forces concurrent execution paths
3. The race condition causes the bad_flp_intr function to access freed memory
4. The attacker can potentially control the contents of the freed memory region, allowing them to redirect execution flow or corrupt critical kernel data structures

The vulnerability can be exploited to achieve arbitrary code execution within the kernel context, leading to complete system compromise, or to cause a kernel panic resulting in denial of service.

Detection Methods for CVE-2022-1652

Indicators of Compromise

• Unexpected kernel panics or system crashes related to the floppy disk subsystem
• Anomalous system calls targeting /dev/fd* floppy device nodes
• Unusual memory corruption or kernel oops messages referencing the floppy driver in system logs
• Processes with unexpected elevated privileges following interaction with floppy disk interfaces

Detection Strategies

• Monitor kernel logs (dmesg) for use-after-free warnings or memory corruption alerts related to the floppy driver
• Implement system call auditing to detect unusual patterns of floppy device access using tools like auditd
• Deploy runtime kernel protection mechanisms such as KASAN (Kernel Address Sanitizer) to detect memory safety violations
• Use SentinelOne's behavioral AI engine to identify exploitation attempts targeting kernel vulnerabilities

Monitoring Recommendations

• Configure log aggregation to centralize kernel messages for analysis across all Linux systems
• Establish baseline behavior for floppy device access (if legitimately used) to identify anomalies
• Implement real-time alerting for kernel oops or panic events that reference the floppy driver module
• Review process execution patterns for programs attempting to interact with legacy hardware interfaces

How to Mitigate CVE-2022-1652

Immediate Actions Required

• Apply the latest kernel security updates from your distribution vendor (Red Hat, Debian, etc.)
• If the floppy disk driver is not required, disable or blacklist the floppy kernel module
• Restrict access to floppy device nodes (/dev/fd*) using appropriate file permissions
• Monitor systems for signs of exploitation attempts while patching is in progress

Patch Information

Security patches addressing CVE-2022-1652 have been released by multiple vendors. Organizations should consult their distribution's security advisory for specific patch information:

• Debian Security Advisory DSA-5173
• NetApp Security Advisory NTAP-20220722-0002
• Red Hat Bug Report #1832397

Update your Linux kernel to the patched version provided by your distribution and reboot the system to apply the fix.

Workarounds

• Blacklist the floppy kernel module by adding blacklist floppy to /etc/modprobe.d/blacklist.conf if floppy disk functionality is not required
• Remove the floppy module from the running kernel using modprobe -r floppy if it is currently loaded
• Restrict user access to floppy device files using chmod 600 /dev/fd* to limit exposure to privileged users only
• Consider implementing mandatory access control (SELinux, AppArmor) policies to further restrict floppy device access

# Disable floppy module to mitigate CVE-2022-1652
# Add to /etc/modprobe.d/blacklist-floppy.conf
echo "blacklist floppy" | sudo tee /etc/modprobe.d/blacklist-floppy.conf

# Remove the module if currently loaded
sudo modprobe -r floppy

# Regenerate initramfs to ensure module is not loaded at boot
sudo update-initramfs -u