CVE-2020-9383
📋 TL;DR
This vulnerability in the Linux kernel's floppy driver allows an out-of-bounds read when accessing the Floppy Disk Controller (FDC) index without proper error checking. Attackers could potentially read kernel memory, leading to information disclosure or system crashes. Systems running Linux kernel versions 3.16 through 5.5.6 with floppy driver functionality are affected.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Leap by Opensuse
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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Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Kernel memory information disclosure leading to privilege escalation or system crash/DoS
Likely Case
System instability or crash due to invalid memory access
If Mitigated
Minimal impact if floppy driver is disabled or system is patched
🎯 Exploit Status
Requires local access and floppy driver interaction
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel 5.5.7 and later
Vendor Advisory: http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html
Restart Required: Yes
Instructions:
1. Update kernel to version 5.5.7 or later
2. Apply kernel patch commit 2e90ca68b0d2
3. Reboot system to load patched kernel
🔧 Temporary Workarounds
Disable floppy driver
linuxRemove or blacklist floppy driver module to prevent exploitation
echo 'blacklist floppy' | sudo tee /etc/modprobe.d/blacklist-floppy.conf
sudo rmmod floppy
🧯 If You Can't Patch
- Disable floppy driver functionality via kernel parameters or module blacklisting
- Restrict local access to prevent unauthorized users from exploiting the vulnerability
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r and verify if between 3.16 and 5.5.6, and check if floppy module is loaded: lsmod | grep floppyCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is 5.5.7 or later: uname -r, and check for patch commit in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages related to floppy driver
- System crashes or instability
Network Indicators:
- None - local vulnerability only
SIEM Query:
search 'kernel: floppy' OR 'kernel: FDC' in system logs🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html
- https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2f9ac30a54dc0181ddac3705cdcf4775d863c530
- https://github.com/torvalds/linux/commit/2e90ca68b0d2f5548804f22f0dd61145516171e3
- https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00012.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
- https://security.netapp.com/advisory/ntap-20200313-0003/
- https://usn.ubuntu.com/4342-1/
- https://usn.ubuntu.com/4344-1/
- https://usn.ubuntu.com/4345-1/
- https://usn.ubuntu.com/4346-1/
- https://www.debian.org/security/2020/dsa-4698
- http://lists.opensuse.org/opensuse-security-announce/2020-03/msg00039.html
- https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=2f9ac30a54dc0181ddac3705cdcf4775d863c530
- https://github.com/torvalds/linux/commit/2e90ca68b0d2f5548804f22f0dd61145516171e3
- https://lists.debian.org/debian-lts-announce/2020/06/msg00011.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00012.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00013.html
- https://security.netapp.com/advisory/ntap-20200313-0003/
- https://usn.ubuntu.com/4342-1/
- https://usn.ubuntu.com/4344-1/
- https://usn.ubuntu.com/4345-1/
- https://usn.ubuntu.com/4346-1/
- https://www.debian.org/security/2020/dsa-4698
