CVE-2023-32250
📋 TL;DR
CVE-2023-32250 is a race condition vulnerability in the Linux kernel's ksmbd SMB server that allows attackers to execute arbitrary code with kernel privileges. This affects systems running Linux kernels with ksmbd enabled, potentially leading to complete system compromise. The vulnerability requires network access to the SMB service.
💻 Affected Systems
- Linux kernel with ksmbd module
📦 What is this software?
H300s by Netapp
H410s by Netapp
H500s by Netapp
H700s by Netapp
Hci by Netapp
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
Full system compromise with kernel-level code execution, allowing attackers to install persistent malware, steal sensitive data, or disrupt critical services.
Likely Case
Remote code execution leading to privilege escalation, data exfiltration, or deployment of ransomware/cryptominers on vulnerable systems.
If Mitigated
Limited impact if ksmbd is disabled or network access is restricted; attackers would need local access to exploit.
🎯 Exploit Status
Exploitation requires race condition timing but has been demonstrated in proof-of-concept code.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel 6.3.4 or later with specific ksmbd fixes
Vendor Advisory: https://access.redhat.com/security/cve/CVE-2023-32250
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Rebuild and reload ksmbd module if using custom builds. 3. Reboot system to apply kernel update.
🔧 Temporary Workarounds
Disable ksmbd module
linuxPrevent loading of the vulnerable ksmbd kernel module
echo 'blacklist ksmbd' >> /etc/modprobe.d/blacklist-ksmbd.conf
rmmod ksmbd
Block SMB ports at firewall
linuxPrevent external access to SMB services
iptables -A INPUT -p tcp --dport 445 -j DROP
iptables -A INPUT -p tcp --dport 139 -j DROP
🧯 If You Can't Patch
- Disable ksmbd service immediately using 'systemctl stop ksmbd' or equivalent
- Implement strict network segmentation to isolate systems with ksmbd enabled
🔍 How to Verify
Check if Vulnerable:
Check if ksmbd module is loaded: lsmod | grep ksmbdCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is patched: uname -r and check against vendor advisories📡 Detection & Monitoring
Log Indicators:
- Unusual SMB connection attempts to port 445/139
- Kernel panic or oops messages related to ksmbd
Network Indicators:
- Multiple rapid SMB2_SESSION_SETUP requests from single source
- Unusual traffic patterns to SMB ports
SIEM Query:
source_port:445 OR source_port:139 AND (event_type:connection_attempt OR event_type:authentication_failure) GROUP BY source_ip COUNT > 10🔗 References
- https://access.redhat.com/security/cve/CVE-2023-32250
- https://bugzilla.redhat.com/show_bug.cgi?id=2208849
- https://security.netapp.com/advisory/ntap-20230824-0004/
- https://www.zerodayinitiative.com/advisories/ZDI-23-698/
- https://access.redhat.com/security/cve/CVE-2023-32250
- https://bugzilla.redhat.com/show_bug.cgi?id=2208849
- https://security.netapp.com/advisory/ntap-20230824-0004/
- https://www.zerodayinitiative.com/advisories/ZDI-23-698/
