---
title: Linux Kernel Update - Azure Instance
description: Detects kernel package updates on Azure VMs, which may indicate patching activity for USN-9026-1
references:
  - https://ubuntu.com/security/notices/USN-9026-1
author: Security Arsenal
date: 2026/01/15
logsource:
  product: linux
  service: package_manager
detection:
  selection:
    - CommandLine|contains:
        - 'apt install linux-image-azure'
        - 'apt upgrade linux-image'
        - 'apt-get install linux-image-azure'
        - 'apt-get upgrade linux-image'
        - 'dpkg -i linux-image'
        - 'yum install kernel'
        - 'dnf install kernel'
  condition: selection
falsepositives:
  - Routine kernel updates
level: informational
---
title: Hypervisor or VM Privilege Escalation Attempt
description: Detects potential privilege escalation attempts or suspicious process activity on hypervisors or VMs that could precede SEV-SNP exploitation
references:
  - https://ubuntu.com/security/notices/USN-9026-1
author: Security Arsenal
date: 2026/01/15
logsource:
  category: process_creation
  product: linux
detection:
  selection:
    - Image|endswith:
        - '/usr/bin/sudo'
        - '/bin/su'
        - '/usr/bin/pkexec'
    - CommandLine|contains:
        - 'sudo -i'
        - 'sudo su'
        - 'pkexec'
  filter:
    User|contains:
      - 'root'
      - 'admin'
      - 'azureuser'
  condition: selection and not filter
falsepositives:
  - Legitimate administrative tasks
level: medium
---
title: Suspicious IOMMU or KVM Activity
description: Monitors for unusual IOMMU or KVM-related process activity that could indicate attempts to exploit SEV-SNP vulnerabilities
references:
  - https://ubuntu.com/security/notices/USN-9026-1
author: Security Arsenal
date: 2026/01/15
logsource:
  category: process_creation
  product: linux
detection:
  selection:
    - Image|endswith:
        - '/usr/bin/qemu-system-x86_64'
        - '/usr/libexec/qemu-kvm'
        - '/usr/bin/kvm'
    - CommandLine|contains:
        - 'iommu'
        - 'sev-snp'
        - 'kvm-amd'
        - '/dev/kvm'
  condition: selection
falsepositives:
  - Legitimate VM management operations
level: low

// Hunt for kernel update activity and potential exploitation attempts on Azure Linux VMs
let timeframe = 7d;
union isfuzzy=true
(Syslog
| where TimeGenerated > ago(timeframe)
| where Computer contains "azure" or Computer contains "vm"
| where SyslogMessage has_any ("kernel", "linux-image", "sev-snp", "iommu", "kvm", "rmp")
| where SyslogMessage has_any ("error", "fail", "denied", "overflow", "out-of-bounds", "corrupt", "exploit")
| project TimeGenerated, Computer, Facility, SeverityLevel, SyslogMessage, ProcessName
| order by TimeGenerated desc),
(CommonSecurityLog
| where TimeGenerated > ago(timeframe)
| where DeviceProduct == "Linux"
| where Message has_any ("kernel", "sev-snp", "iommu", "kvm", "rmp")
| where Message has_any ("error", "fail", "denied", "overflow", "out-of-bounds", "corrupt", "exploit")
| project TimeGenerated, DeviceName, DeviceProduct, Message, SourceIP, DestinationIP
| order by TimeGenerated desc)
| summarize count() by Computer, bin(TimeGenerated, 1h)
| where count_ > 5
| order by count_ desc

-- Hunt for kernel version and virtualization processes on Linux systems
SELECT 
    Pid, 
    Name, 
    CommandLine, 
    Exe, 
    Username, 
    CreateTime,
    PPid,
    PName
FROM pslist()
WHERE 
    CommandLine =~ '(qemu|kvm|libvirt|virtio|iommu|sev-snp)'
    OR Exe =~ '/usr/bin/qemu'
    OR Exe =~ '/usr/libexec/qemu'
    OR Name =~ 'kvm'
    OR Name =~ 'qemu'

#!/bin/bash
# USN-9026-1 Linux Kernel (Azure) Vulnerability Remediation Script
# For Ubuntu systems running on Microsoft Azure

set -e

echo "[+] Starting USN-9026-1 remediation check..."

# Check if running on Azure
if ! dmidecode -s system-manufacturer | grep -qi "microsoft corporation"; then
    echo "[!] Warning: This system may not be running on Microsoft Azure"
fi

# Check current kernel version
echo "[+] Current kernel version: $(uname -r)"

# Update package lists
echo "[+] Updating package lists..."
sudo apt-get update

# Check for available kernel updates
echo "[+] Checking for kernel updates..."
KERNEL_UPDATE=$(apt list --upgradable 2>/dev/null | grep linux-image-azure || true)

if [ -z "$KERNEL_UPDATE" ]; then
    echo "[+] No kernel updates available. System may already be patched."
else
    echo "[+] Kernel update available: $KERNEL_UPDATE"
    echo "[+] Installing kernel update..."
    sudo apt-get install -y linux-image-azure
    
    # Check if reboot is required
    if [ -f /var/run/reboot-required ]; then
        echo "[!] REBOOT REQUIRED to complete kernel update"
        echo "[!] Please reboot the system as soon as possible"
    fi
fi

# Verify SEV-SNP status
echo "[+] Checking SEV-SNP status..."
if [ -f /sys/module/kvm_amd/parameters/sev_snp ]; then
    SEV_SNP_STATUS=$(cat /sys/module/kvm_amd/parameters/sev_snp)
    echo "[+] SEV-SNP status: $SEV_SNP_STATUS"
    if [ "$SEV_SNP_STATUS" = "Y" ]; then
        echo "[+] SEV-SNP is enabled. Ensure kernel is updated to mitigate CVE-2023-20585"
    else
        echo "[+] SEV-SNP is not currently enabled"
    fi
else
    echo "[!] SEV-SNP parameter not found. System may not support SEV-SNP or module not loaded"
fi

# Check for other kernel updates
echo "[+] Checking for other security updates..."
sudo unattended-upgrades --dry-run -d 2>&1 | grep -i "kernel\|security" || echo "[+] No additional security updates found"

echo "[+] Remediation check complete"

2. **Limit Hypervisor Access**:
   - Restrict access to the Azure host system to essential personnel only
   - Use Azure RBAC to control VM management permissions
   - Enable Azure Privileged Identity Management (PIM) for just-in-time access

3. **Network Isolation**:
   - Place SEV-SNP VMs in isolated subnets with no direct internet access
   - Use Azure Firewall or Network Virtual Appliances (NVAs) to inspect traffic

### Vendor Resources

- **Ubuntu Security Notice:** [USN-9026-1](https://ubuntu.com/security/notices/USN-9026-1)
- **Azure Confidential Computing Documentation:** [Azure SEV-SNP VMs](https://learn.microsoft.com/en-us/azure/confidential-computing/confidential-vm-overview)
- **Linux Kernel CVE Details:** [CVE-2023-20585](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-20585)
- **AMD Security Advisory:** [AMD-SB-3009](https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-3009) (related SEV-SNP issues)

### CISA Deadlines

As of this writing, CVE-2023-20585 is **not** listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. However, organizations should treat this as a high-priority patch due to the sensitivity of SEV-SNP protected workloads.

## Related Resources

[Security Arsenal Penetration Testing Services](https://securityarsenal.com/services/penetration-testing)
[AlertMonitor Platform](https://securityarsenal.com/products/alertmonitor)
[Book a SOC Assessment](https://securityarsenal.com/contact)
[vulnerability-management Intel Hub](https://securityarsenal.com/intel/incident-response)