CVE-2023-45871: Linux Kernel IGB Driver Buffer Overflow

CVE-2023-45871 Overview

CVE-2023-45871 is a buffer size vulnerability discovered in the Intel IGB (Intel Gigabit Ethernet) network driver within the Linux kernel. The vulnerability exists in drivers/net/ethernet/intel/igb/igb_main.c where the buffer size may not be adequate to handle frames larger than the configured MTU (Maximum Transmission Unit). This improper buffer calculation falls under CWE-131 (Incorrect Calculation of Buffer Size), which can lead to memory corruption when processing oversized network frames.

Critical Impact

An attacker on an adjacent network could potentially exploit this buffer size miscalculation to achieve code execution, data corruption, or denial of service on systems running vulnerable Linux kernel versions with Intel IGB network adapters.

Affected Products

• Linux Kernel versions before 6.5.3
• Debian Linux 10.0
• Systems utilizing Intel IGB network drivers

Discovery Timeline

• October 15, 2023 - CVE-2023-45871 published to NVD
• May 5, 2025 - Last updated in NVD database

Technical Details for CVE-2023-45871

Vulnerability Analysis

The vulnerability resides in the IGB driver's frame handling logic within igb_main.c. When network frames arrive that exceed the configured MTU boundary, the driver's buffer allocation may be insufficient to properly contain the incoming data. This improper calculation of buffer size creates a condition where memory adjacent to the allocated buffer could be overwritten.

The IGB driver is widely deployed across enterprise and consumer environments as it supports Intel Gigabit Ethernet adapters, making this vulnerability significant for server infrastructure, workstations, and embedded systems utilizing Intel networking hardware.

The adjacent network attack vector requires an attacker to be on the same network segment (such as the same VLAN or physical network) as the target system. While this limits remote exploitation from the internet, it presents a substantial risk in data center environments, shared hosting infrastructure, and enterprise networks where lateral movement is possible.

Root Cause

The root cause is CWE-131: Incorrect Calculation of Buffer Size. The IGB driver fails to properly account for frames that exceed the MTU when allocating receive buffers. This miscalculation means the driver may allocate a buffer that is too small for certain network frames, leading to potential out-of-bounds memory access when the frame data is written to the undersized buffer.

Attack Vector

The attack vector requires adjacent network access. An attacker positioned on the same Layer 2 network segment as the target could craft and transmit malicious network frames exceeding the MTU boundary. When these frames are processed by a vulnerable IGB driver, the inadequate buffer size could result in memory corruption. Successful exploitation could lead to unauthorized code execution with kernel privileges, complete system compromise, or denial of service through kernel panic.

The vulnerability mechanism involves sending specially crafted Ethernet frames to a system with a vulnerable Intel IGB network adapter. When the driver attempts to process these oversized frames with an inadequately sized buffer, memory corruption occurs. Technical details of the fix can be found in the Linux Kernel Commit bb5ed01.

Detection Methods for CVE-2023-45871

Indicators of Compromise

• Unexpected kernel panics or system crashes on systems with Intel IGB network adapters
• Unusual memory corruption errors in kernel logs related to network processing
• Abnormal network traffic patterns with oversized frames targeting IGB-equipped systems
• Kernel oops messages referencing igb_main.c or IGB driver functions

Detection Strategies

• Monitor kernel logs (dmesg, /var/log/kern.log) for IGB driver errors or memory corruption warnings
• Deploy network intrusion detection to identify anomalous frame sizes on network segments with vulnerable systems
• Implement kernel integrity monitoring to detect unexpected modifications
• Use vulnerability scanning tools to identify systems running kernel versions prior to 6.5.3

Monitoring Recommendations

• Enable enhanced kernel logging for network driver subsystems
• Configure network monitoring to alert on unusual Ethernet frame characteristics
• Implement host-based detection for kernel anomalies and unexpected crashes
• Review system stability metrics for Intel IGB-equipped systems for unexplained instability

How to Mitigate CVE-2023-45871

Immediate Actions Required

• Update Linux kernel to version 6.5.3 or later on all affected systems
• Prioritize patching for systems with Intel IGB network adapters exposed to untrusted network segments
• Review network segmentation to limit adjacent network exposure for critical systems
• Monitor affected systems for signs of exploitation until patches are applied

Patch Information

The vulnerability has been addressed in Linux kernel version 6.5.3. The fix is available through the official kernel commit bb5ed01cd2428cd25b1c88a3a9cba87055eb289f. Organizations should update their kernels through their distribution's package management system or by applying the patch directly. Additional advisories have been released by Debian and NetApp for their respective platforms. The complete changelog is available in the Linux Kernel ChangeLog 6.5.3.

Workarounds

• Implement strict network segmentation to isolate systems with Intel IGB adapters from untrusted network segments
• Consider using alternative network drivers or adapters where feasible until patching is complete
• Enable additional network filtering at switches and routers to limit oversized frame transmission
• Monitor network traffic for anomalous behavior targeting systems with Intel networking hardware

# Check current kernel version
uname -r

# Verify if IGB driver is in use
lsmod | grep igb

# Check for Intel IGB network adapters
lspci | grep -i ethernet | grep -i intel

# Update kernel on Debian/Ubuntu systems
sudo apt update && sudo apt upgrade linux-image-$(uname -r)

# Update kernel on RHEL/CentOS systems
sudo yum update kernel