CVE-2023-52885
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's SUNRPC subsystem that can lead to kernel crashes or potential code execution. It affects systems running NFS servers or other SUNRPC services. The vulnerability occurs when a freed listener socket is accessed during TCP data processing.
💻 Affected Systems
- Linux kernel
📦 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...
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
Kernel panic leading to system crash, or potential kernel code execution with elevated privileges
Likely Case
System instability, kernel crashes, or denial of service affecting NFS/RPC services
If Mitigated
Limited to denial of service if exploit attempts fail or system has additional protections
🎯 Exploit Status
Exploitation requires network access to SUNRPC services and specific timing conditions
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits 42725e5c1b181b757ba11d804443922982334d9b or later
Vendor Advisory: https://git.kernel.org/stable/c/42725e5c1b181b757ba11d804443922982334d9b
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable SUNRPC services
linuxStop NFS server and other SUNRPC-dependent services
systemctl stop nfs-server
systemctl disable nfs-server
Firewall blocking
linuxBlock access to SUNRPC ports (typically 2049 for NFS)
iptables -A INPUT -p tcp --dport 2049 -j DROP
iptables -A INPUT -p udp --dport 2049 -j DROP
🧯 If You Can't Patch
- Disable NFS server and other SUNRPC services if not required
- Implement strict network segmentation and firewall rules to limit access to SUNRPC ports
🔍 How to Verify
Check if Vulnerable:
Check if running NFS server and kernel version matches affected range: systemctl status nfs-server && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and NFS services are stable after patch📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN use-after-free reports in dmesg
- NFS service crashes
Network Indicators:
- Multiple connection attempts to port 2049 with malformed data
- Unusual traffic patterns to SUNRPC ports
SIEM Query:
source="kernel" AND ("KASAN" OR "use-after-free" OR "svc_tcp_listen_data_ready")🔗 References
- https://git.kernel.org/stable/c/42725e5c1b181b757ba11d804443922982334d9b
- https://git.kernel.org/stable/c/7e1f989055622fd086c5dfb291fc72adf5660b6f
- https://git.kernel.org/stable/c/c7b8c2d06e437639694abe76978e915cfb73f428
- https://git.kernel.org/stable/c/cd5ec3ee52ce4b7e283cc11facfa420c297c8065
- https://git.kernel.org/stable/c/dfc896c4a75cb8cd7cb2dfd9b469cf1e3f004254
- https://git.kernel.org/stable/c/ef047411887ff0845afd642d6a687819308e1a4e
- https://git.kernel.org/stable/c/fbf4ace39b2e4f3833236afbb2336edbafd75eee
- https://git.kernel.org/stable/c/fc80fc2d4e39137869da3150ee169b40bf879287
- https://git.kernel.org/stable/c/42725e5c1b181b757ba11d804443922982334d9b
- https://git.kernel.org/stable/c/7e1f989055622fd086c5dfb291fc72adf5660b6f
- https://git.kernel.org/stable/c/c7b8c2d06e437639694abe76978e915cfb73f428
- https://git.kernel.org/stable/c/cd5ec3ee52ce4b7e283cc11facfa420c297c8065
- https://git.kernel.org/stable/c/dfc896c4a75cb8cd7cb2dfd9b469cf1e3f004254
- https://git.kernel.org/stable/c/ef047411887ff0845afd642d6a687819308e1a4e
- https://git.kernel.org/stable/c/fbf4ace39b2e4f3833236afbb2336edbafd75eee
- https://git.kernel.org/stable/c/fc80fc2d4e39137869da3150ee169b40bf879287
