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The GitLab Security Tech Note from February 2025 discusses the threat posed by malicious browser extensions. These extensions can compromise user privacy and security by stealing sensitive information, injecting malicious code, and performing unauthorized actions. The note highlights various techniques used by attackers to distribute and disguise these extensions, such as mimicking legitimate software and exploiting browser vulnerabilities.
The report includes some alarming statistics: over 16 malicious Chrome extensions were discovered, affecting approximately 3.2 million users. Additionally, more than half of the browser extensions analyzed required excessive permissions, posing significant risks by allowing threat actors to access web traffic, manipulate browser tabs, and harvest sensitive data.
To mitigate these threats in a MDE organization, you can run the below DefenderXDR custom detection rule to identify all impacted endpoints and also quarantine further extension from installing.
DefenderXDR Custom Detection:
[kql]
let maliciousExtensions = dynamic([“extension_id_1”, “extension_id_2”, “extension_id_3”]);
DeviceEvents
| where ActionType == “BrowserExtensionInstalled”
| where InitiatingProcessFileName =~ “chrome.exe”
| where tostring(parse_json(AdditionalFields).ExtensionId) in (maliciousExtensions)
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, AdditionalFields
[/kql]
Tech Note – Malicious Browser Extensions Impacting at Least 3.2 Million Users:
GitLab Tech Note
What Undercode Say:
The rise of malicious browser extensions is a significant threat to cybersecurity, as they can easily bypass traditional security measures and compromise user data. The GitLab report highlights the importance of monitoring and managing browser extensions within an organization. The DefenderXDR custom detection rule provided is a practical approach to identifying and mitigating these threats.
In addition to the KQL query, here are some other commands and practices to enhance your cybersecurity posture:
1. Linux Command to List Installed Browser Extensions:
ls ~/.config/google-chrome/Default/Extensions/
2. Windows PowerShell Command to Remove Malicious Extensions:
Get-ChildItem -Path "$env:LOCALAPPDATA\Google\Chrome\User Data\Default\Extensions" | ForEach-Object {
if ($<em>.Name -in @("extension_id_1", "extension_id_2")) {
Remove-Item -Recurse -Force $</em>.FullName
}
}
- Linux Command to Monitor Network Traffic for Suspicious Activity:
sudo tcpdump -i eth0 -w capture.pcap
4. Windows Command to Check for Suspicious Processes:
[cmd]
tasklist /v | findstr /i “chrome”
[/cmd]
5. Linux Command to Block Malicious IPs:
sudo iptables -A INPUT -s malicious_ip -j DROP
6. Windows Command to Flush DNS Cache:
[cmd]
ipconfig /flushdns
[/cmd]
7. Linux Command to Check for Open Ports:
sudo netstat -tuln
8. Windows Command to Disable a Suspicious Service:
[cmd]
sc config “suspicious_service” start= disabled
[/cmd]
9. Linux Command to Check for Rootkits:
sudo rkhunter --check
10. Windows Command to Scan for Malware:
[cmd]
MRT.exe
[/cmd]
The GitLab report underscores the need for continuous monitoring and proactive measures to combat the ever-evolving threat landscape. By leveraging tools like DefenderXDR and implementing the above commands, organizations can significantly reduce their risk exposure. Always ensure that your systems are up-to-date with the latest security patches and that your team is trained to recognize and respond to potential threats.
For further reading and resources, visit the GitLab Tech Note and explore more about DefenderXDR Custom Detection.
References:
Hackers Feeds, Undercode AI
