Source: cve@mitre.org
The permissions for the /dev/audio device on Solaris 2.2 and earlier, and SunOS 4.1.x, allow any local user to read from the device, which could be used by an attacker to monitor conversations happening near a machine that has a microphone.
Local privilege escalation is possible on vulnerable Solaris and SunOS systems due to insecure permissions on the /dev/audio device. This allows any local user to eavesdrop on audio input, potentially leading to sensitive information disclosure and further compromise.
Step 1: Access Device: A local user logs into the vulnerable system.
Step 2: Identify Device: The user identifies the /dev/audio device using commands like ls -l /dev/audio to confirm its existence and permissions.
Step 3: Read Audio Data: The user utilizes a program (e.g., a simple shell script or a compiled binary) to read data from /dev/audio. This program opens the device for reading and continuously captures the audio stream.
Step 4: Data Capture: The program captures the audio data, which includes any sound picked up by a connected microphone.
Step 5: Data Exfiltration (Optional): The captured audio data can be saved to a file or transmitted to a remote location, potentially using network tools or other available utilities, allowing the attacker to eavesdrop on conversations.
The vulnerability stems from a fundamental design flaw in the operating system's device driver permissions. The /dev/audio device, responsible for audio input and output, is configured with permissions that allow any local user to read from it. This means any user on the system can access the audio stream without authentication or authorization. The root cause is a lack of access control on the device, failing to restrict access to privileged users or groups. This design flaw allows for unauthorized access to sensitive audio data, enabling eavesdropping and potential data exfiltration.
Due to the age of the vulnerability, specific APT groups or malware families are unlikely to be directly targeting this. However, the techniques used (eavesdropping) are common in more sophisticated attacks. This vulnerability is not listed on the CISA KEV.
Monitor system logs for access attempts to /dev/audio by non-privileged users.
Analyze network traffic for unusual data transfers originating from the affected system, especially if audio data is suspected.
Implement file integrity monitoring to detect any unauthorized modifications to the /dev/audio device permissions or related system files.
Review user activity logs for suspicious commands related to audio recording or playback.
Upgrade to a supported operating system version. This is the most effective remediation.
If upgrading is not possible, restrict access to the /dev/audio device. Change the permissions on /dev/audio to allow access only to the root user or a specific audio group.
Implement a host-based intrusion detection system (HIDS) to monitor for unauthorized access attempts to the device.
Regularly audit system configurations and permissions to ensure they align with security best practices.
Disable the audio device if it is not required for system functionality.