CVE-2021-20793 – This CVE describes an untrusted search path vul... (How to Fix)

Q: What is the severity of CVE-2021-20793?

CVE-2021-20793 has a CVSS score of 7.8 (HIGH). This CVE describes an untrusted search path vulnerability in Sony Audio USB Driver and HAP Music Transfer installers. Attackers can place malicious DLLs in directories searched by these installers, leading to privilege escalation and arbitrary code execution. Users of affected Sony software versions are vulnerable.

📋 TL;DR

This CVE describes an untrusted search path vulnerability in Sony Audio USB Driver and HAP Music Transfer installers. Attackers can place malicious DLLs in directories searched by these installers, leading to privilege escalation and arbitrary code execution. Users of affected Sony software versions are vulnerable.

💻 Affected Systems

Products:

Sony Audio USB Driver
HAP Music Transfer

Versions: Sony Audio USB Driver V1.10 and prior, HAP Music Transfer Ver.1.3.0 and prior

Operating Systems: Windows

Default Config Vulnerable: ⚠️ Yes

Notes: Vulnerability exists in the installer components, not necessarily the running applications. Requires attacker to place DLL in specific directories.

📦 What is this software?

Audio Usb Driver by Sony

View all CVEs affecting Audio Usb Driver →

Hap Music Transfer by Sony

View all CVEs affecting Hap Music Transfer →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Full system compromise with administrative privileges, allowing installation of persistent malware, data theft, and complete control of the affected system.

🟠

Likely Case

Local privilege escalation leading to installation of additional malware, credential theft, or lateral movement within the network.

🟢

If Mitigated

Limited to local user context with proper application whitelisting and DLL search path restrictions in place.

🌐 Internet-Facing: LOW - This is a local attack requiring access to the target system or tricking users into running malicious installers.

🏢 Internal Only: MEDIUM - Internal attackers with local access could exploit this for privilege escalation, but requires specific conditions and user interaction.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access to place malicious DLL and knowledge of installer search paths. Social engineering could trick users into running installers from compromised locations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Update to versions after Sony Audio USB Driver V1.10 and HAP Music Transfer Ver.1.3.0

Vendor Advisory: https://www.sony.co.uk/electronics/support/software/00266642

Restart Required: Yes

Instructions:

1. Visit Sony support pages for affected products. 2. Download and install updated versions. 3. Restart system after installation. 4. Verify installation completed successfully.

🔧 Temporary Workarounds

Restrict DLL search paths

windows

Use Windows policies to restrict DLL search paths and prevent loading from untrusted directories

Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Control\Session Manager' -Name 'SafeDllSearchMode' -Value 1

Application whitelisting

windows

Implement application control policies to only allow trusted installers to run

🧯 If You Can't Patch

Remove or disable affected Sony software if not required
Implement strict user privilege management to limit local attack surface

🔍 How to Verify

Check if Vulnerable:

Check installed software versions: Sony Audio USB Driver ≤ V1.10 or HAP Music Transfer ≤ Ver.1.3.0

Check Version:

wmic product get name,version | findstr /i "sony"

Verify Fix Applied:

Verify installed versions are newer than affected versions through Control Panel or software properties

📡 Detection & Monitoring

Log Indicators:

Windows Event Logs showing DLL loading from unusual paths
Process creation events for Sony installers from unexpected locations

Network Indicators:

Unusual outbound connections following installer execution
DNS queries to suspicious domains after software installation

SIEM Query:

EventID=4688 AND (ProcessName LIKE '%sony%' OR ProcessName LIKE '%install%') AND CommandLine CONTAINS '.dll'

📊 Metadata

CVE ID: CVE-2021-20793

CVSS v3 Score: 7.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-427

Published: August 26, 2021

Last Updated: November 21, 2024

🔗 References

https://jvn.jp/en/jp/JVN80288258/index.html Third Party Advisory
https://www.sony.co.uk/electronics/support/software/00266642 Product,Vendor Advisory
https://www.sony.co.uk/electronics/support/software/00266749 Product,Vendor Advisory
https://www.sony.co.uk/electronics/support/software/00266758 Product,Vendor Advisory
https://jvn.jp/en/jp/JVN80288258/index.html Third Party Advisory
https://www.sony.co.uk/electronics/support/software/00266642 Product,Vendor Advisory
https://www.sony.co.uk/electronics/support/software/00266749 Product,Vendor Advisory
https://www.sony.co.uk/electronics/support/software/00266758 Product,Vendor Advisory

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🔗 Related Vulnerabilities

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