CVE-2022-25265: Linux Kernel RCE Vulnerability

CVE-2022-25265 Overview

CVE-2022-25265 is a vulnerability in the Linux kernel through version 5.16.10 where certain binary files may have the exec-all attribute if they were built in approximately 2003 (e.g., with GCC 3.2.2 and Linux kernel 2.4.20). This can cause execution of bytes located in supposedly non-executable regions of a file, potentially allowing local attackers to escalate privileges or execute arbitrary code.

Critical Impact

Local attackers can exploit legacy ELF binaries to execute code from non-executable memory regions, bypassing execution protection mechanisms and potentially gaining elevated privileges on affected Linux systems.

Affected Products

• Linux Kernel (through version 5.16.10)
• NetApp H300S/H500S/H700S Firmware
• NetApp H300E/H500E/H700E Firmware
• NetApp H410S/H410C Firmware
• NetApp Baseboard Management Controller Firmware

Discovery Timeline

• 2022-02-16 - CVE-2022-25265 published to NVD
• 2022-03-18 - NetApp releases security advisory ntap-20220318-0005
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-25265

Vulnerability Analysis

This vulnerability stems from a legacy issue in how the Linux kernel handles ELF (Executable and Linkable Format) binary attributes. Binary files compiled around 2003 using older toolchains such as GCC 3.2.2 targeting Linux kernel 2.4.20 may inadvertently have the exec-all attribute set. This attribute designation causes the kernel to treat normally non-executable regions of the binary as executable.

The core issue lies in the x86 architecture's ELF handling code, specifically in arch/x86/include/asm/elf.h, where the execution protection logic may not properly enforce non-executable permissions for these legacy binaries. This represents a form of improper control of dynamically-managed code resources (CWE-913).

Root Cause

The root cause is an improper handling of ELF binary metadata for files compiled with specific older toolchain combinations. The Linux kernel's ELF loader does not adequately validate or enforce execution permissions for binary segments when processing these legacy binaries, allowing the exec-all attribute to override intended non-executable protections.

This architectural oversight means that data segments or other regions that should be marked as non-executable can be executed, undermining fundamental memory protection mechanisms like NX (No-Execute) bit enforcement.

Attack Vector

The attack requires local access to the system and the presence of or ability to introduce a specially crafted legacy ELF binary. An attacker with low privileges can exploit this vulnerability by:

1. Identifying or creating an ELF binary with the exec-all attribute characteristic of 2003-era compilations
2. Placing malicious code in what would normally be a non-executable region of the binary
3. Triggering execution of the binary, causing the kernel to execute the malicious code from the supposedly protected memory region

This bypasses standard execution flow protections and can lead to arbitrary code execution with the privileges of the running process, potentially enabling privilege escalation if combined with other vulnerabilities or misconfigurations.

The vulnerability manifests in the ELF loading mechanism where execution permissions are determined. The relevant code path can be examined in the Linux kernel source on GitHub. A proof-of-concept demonstrating this execution protection bypass is available at the exec-prot-bypass repository.

Detection Methods for CVE-2022-25265

Indicators of Compromise

• Presence of ELF binaries compiled with GCC 3.2.2 or similar era toolchains
• Binaries with unusual segment permissions showing executable flags on data sections
• Unexpected code execution patterns from processes running legacy binaries
• Audit logs showing execution of files with anomalous ELF headers

Detection Strategies

• Scan file systems for ELF binaries with the exec-all attribute using tools like readelf or custom scripts to inspect ELF headers
• Monitor for process execution anomalies where code runs from unexpected memory regions
• Implement file integrity monitoring to detect introduction of legacy or crafted binaries
• Deploy endpoint detection solutions capable of identifying exploitation attempts targeting memory protection bypasses

Monitoring Recommendations

• Enable Linux audit subsystem (auditd) to log binary executions and track unusual ELF file access patterns
• Configure SentinelOne agents to monitor for exploitation behaviors associated with memory protection bypasses
• Review system logs for unexpected process crashes or segmentation faults that may indicate exploitation attempts
• Monitor for privilege escalation attempts following execution of legacy binaries

How to Mitigate CVE-2022-25265

Immediate Actions Required

• Update the Linux kernel to a patched version that properly enforces execution protections for legacy binaries
• Audit systems for the presence of ELF binaries compiled with 2003-era toolchains (GCC 3.2.2, kernel 2.4.20)
• Remove or recompile any identified legacy binaries with modern toolchains
• Apply firmware updates for affected NetApp devices as outlined in their security advisory

Patch Information

Organizations should update their Linux kernel installations and apply vendor-specific firmware updates. NetApp has released security advisory ntap-20220318-0005 addressing this vulnerability for their affected products including H300S, H500S, H700S, H300E, H500E, H700E, H410S, H410C, and Baseboard Management Controller firmware.

Consult your Linux distribution vendor for specific kernel patches addressing CVE-2022-25265.

Workarounds

• Identify and remove legacy ELF binaries from production systems until they can be recompiled with modern toolchains
• Implement application whitelisting to prevent execution of unauthorized or legacy binaries
• Use SELinux or AppArmor policies to restrict execution permissions and enforce mandatory access controls
• Consider isolating systems that must run legacy applications in network segments with restricted access

# Scan for potentially affected ELF binaries by checking compilation timestamps and attributes
find /usr/bin /usr/sbin /usr/local/bin -type f -executable -exec sh -c '
    file "$1" | grep -q "ELF" && readelf -h "$1" 2>/dev/null | grep -q "Version"
' _ {} \; -print

# Use readelf to inspect ELF segment permissions
readelf -l /path/to/binary | grep -E "LOAD|GNU_STACK"