CVE-2024-5256
📋 TL;DR
An integer underflow vulnerability in SMB2 message handling on Sonos Era 100 smart speakers allows network-adjacent attackers to read sensitive memory contents without authentication. This information disclosure could be combined with other vulnerabilities to achieve remote code execution as root. Only Sonos Era 100 devices on the same network segment are affected.
💻 Affected Systems
- Sonos Era 100
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers combine this information disclosure with other vulnerabilities to achieve remote code execution with root privileges, potentially taking full control of the device.
Likely Case
Attackers on the same network can read sensitive memory contents from the device, potentially exposing credentials, encryption keys, or other sensitive data.
If Mitigated
With proper network segmentation, the impact is limited to information disclosure from the device's memory to attackers on the same network segment.
🎯 Exploit Status
Exploitation requires network access and understanding of SMB2 protocol. The vulnerability itself is information disclosure but could be chained with other vulnerabilities for code execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Sonos app for latest firmware
Vendor Advisory: https://www.sonos.com/en-us/security
Restart Required: Yes
Instructions:
1. Open Sonos app 2. Go to Settings > System > System Updates 3. Check for updates 4. Apply any available updates 5. Device will restart automatically
🔧 Temporary Workarounds
Network Segmentation
allIsolate Sonos devices on separate VLAN or network segment from sensitive systems
Disable SMB2 if not needed
allIf SMB file sharing is not required, disable SMB services on the device
🧯 If You Can't Patch
- Segment Sonos devices on isolated network/VLAN away from sensitive systems
- Implement network access controls to restrict which devices can communicate with Sonos devices
🔍 How to Verify
Check if Vulnerable:
Check Sonos app: Settings > System > About My System > check Era 100 firmware versionCheck Version:
Not applicable - use Sonos mobile app interfaceVerify Fix Applied:
Verify firmware version is updated to latest available in Sonos app📡 Detection & Monitoring
Log Indicators:
- Unusual SMB2 traffic patterns to Sonos devices
- Multiple malformed SMB2 packets from single source
Network Indicators:
- SMB2 packets with unusual length fields targeting port 445 on Sonos devices
- Repeated connection attempts to Sonos SMB services
SIEM Query:
source_ip:* AND dest_ip:sonos_device_ip AND protocol:SMB2 AND (packet_length < threshold OR malformed_packet:true)