CVE-2023-1194
📋 TL;DR
This vulnerability allows an attacker to trigger an out-of-bounds memory read in the KSMBD (in-kernel Samba server) and CIFS components of the Linux kernel by sending a malformed CREATE command. It affects Linux systems with KSMBD enabled, potentially leading to information disclosure or system crashes. Users of affected Linux kernel versions with KSMBD configured are at risk.
💻 Affected Systems
- Linux kernel with KSMBD module
📦 What is this software?
Fedora by Fedoraproject
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 →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
Exploitation could lead to kernel memory disclosure, enabling information leaks or system instability, potentially facilitating further attacks like privilege escalation or denial of service.
Likely Case
Most probable impact is denial of service (system crash or kernel panic) due to invalid memory access, with possible information disclosure from kernel memory.
If Mitigated
If proper controls like network segmentation and access restrictions are in place, impact is limited to denial of service within the affected system, with reduced risk of data exposure.
🎯 Exploit Status
Exploitation requires sending a crafted network packet to KSMBD, but no public proof-of-concept has been disclosed as of the advisory dates.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor-specific patches (e.g., Red Hat kernel updates, Linux kernel commits like those in stable-commits list).
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2023-1194
Restart Required: Yes
Instructions:
1. Update the Linux kernel to a patched version from your distribution's repository. 2. For Red Hat systems, use 'yum update kernel' or 'dnf update kernel'. 3. Reboot the system to apply the kernel update.
🔧 Temporary Workarounds
Disable KSMBD module
linuxPrevents exploitation by unloading the KSMBD kernel module if not required.
sudo modprobe -r ksmbd
Block network access to KSMBD
linuxRestrict access to KSMBD services using firewall rules to limit exposure.
sudo iptables -A INPUT -p tcp --dport 445 -j DROP
sudo iptables -A INPUT -p tcp --dport 139 -j DROP
🧯 If You Can't Patch
- Disable KSMBD service if not essential to reduce attack surface.
- Implement network segmentation to isolate systems with KSMBD from untrusted networks.
🔍 How to Verify
Check if Vulnerable:
Check if KSMBD module is loaded and kernel version is unpatched: run 'lsmod | grep ksmbd' and 'uname -r', then compare with vendor advisories.Check Version:
uname -rVerify Fix Applied:
After patching, verify the kernel version is updated and KSMBD module is still disabled or patched: run 'uname -r' and check for absence of vulnerability in vendor patch notes.📡 Detection & Monitoring
Log Indicators:
- Kernel logs (dmesg) showing crashes or warnings related to KSMBD or memory access errors.
- System logs with entries for KSMBD service failures or unexpected restarts.
Network Indicators:
- Unusual network traffic to port 445 (SMB) with malformed CREATE commands, detectable via IDS/IPS signatures.
SIEM Query:
Example: search for 'ksmbd' AND ('panic' OR 'oops' OR 'BUG') in kernel logs within your SIEM.🔗 References
- https://access.redhat.com/security/cve/CVE-2023-1194
- https://bugzilla.redhat.com/show_bug.cgi?id=2154176
- https://security.netapp.com/advisory/ntap-20231221-0006/
- https://www.spinics.net/lists/stable-commits/msg303065.html
- https://access.redhat.com/security/cve/CVE-2023-1194
- https://bugzilla.redhat.com/show_bug.cgi?id=2154176
- https://security.netapp.com/advisory/ntap-20231221-0006/
- https://www.spinics.net/lists/stable-commits/msg303065.html
