Detecting and Mitigating Portable Applications in Enterprise Environments

Author: Vinay Kumar Patel Advisor: Ankit Rai Date: October 13, 2024

Abstract:- Portable applications (portable apps) pose a security challenge in enterprise environments, as they bypass traditional installation footprints like registry entries and installation logs. Without detection measures, they can compromise network security by circumventing software management policies. This paper explores methods for detecting portable applications, highlights the risks they present, and discusses strategies for mitigating their impact through file path monitoring, application control policies, and centralized security tools.

1. Introduction In a corporate setting, portable applications provide flexibility but also increase the risk of security breaches by bypassing software restrictions. These apps typically do not require installation and can be executed directly from external drives or specific user folders, making it difficult for administrators to track and control them. This paper aims to outline techniques to detect portable apps, particularly in large organizations, and provide best practices for mitigating their risks.

2. Overview of Portable Applications 2.1 Characteristics of Portable Applications Portable apps are designed to run without the need for traditional installation procedures. They can be executed from external devices like USB drives, shared folders, or user directories. Unlike conventional software, portable apps leave minimal traces, making them difficult to detect. Their execution does not generate registry keys, installation logs, or modify system paths, leading to several security challenges.

Examples of portable application formats include: Portable Application Format (PAF): Used by platforms like PortableApps.com to bundle applications for portability. Pathfinder Adventure File (PAF): Employed in role-playing games for managing assets. Parallax Asset File (PAF): Utilized in the gaming industry to store graphic files.

2.2 Creation of Portable Applications Portable apps can be created using various tools such as PortableApps.com, Enigma Virtual Box, Cameyo, or even with utilities like WinRAR to build Self-Extracting Archives (SFX). Each tool provides different functionalities for packaging software into a portable form, allowing users to transfer and execute apps from any machine without administrative privileges. WinRAR Method for Creating Portable Applications: Select all the installed files and add them to a WinRAR archive. Under "Archiving options," select "Create SFX archive." Go to "Advanced" and select "SFX options," then click on "Setup." Copy the application name and paste it into "Run after extraction" followed by ".exe". Select "Modes," click on "Unpack to temporary folder," and under "Silent mode," click on "Hide all." Go to the "Update" tab and select "Extract and replace files" and "Overwrite all files." Apply the settings. You'll find the portable application in the installed folder as "nameportable.exe". You can now move this single .exe file anywhere, and it will run from a temp folder.

3. Security Risks of Portable Applications 3.1 Security Risks Overview Portable applications pose several risks to enterprise security, including: Bypassing Security Policies: Since portable apps are not installed traditionally, they can bypass whitelisting policies or application control solutions. Increased Malware Exposure: Portable apps downloaded from untrusted sources can contain malware, which can execute without raising alarms. Data Leakage: Executing sensitive or unauthorized applications can lead to data leakage, especially if users bring in personal applications on external drives. Lack of Accountability: Portable apps can make it harder to track user behavior, as they do not generate typical logs.

4. Methods for Detecting Portable Applications 4.1 Monitoring File Extensions and Paths One effective method for detecting portable apps is monitoring specific file extensions or file paths. For instance, file extensions like .paf.exe can be targeted to detect portable applications related to the PortableApps platform. Monitoring execution from external drives (such as E:\\\\ or F:\\\\) can also provide insights into unauthorized software activity. Microsoft Sentinel Query Example:

I’ve developed a precise KQL query using Microsoft Defender for Office 365 and Endpoint to detect abuse scenarios. This helps defenders mitigate the risk of portable app attacks that leverage trusted platform app names to evade detection. You can download the KQL query from my GitHub repository. Here’s my Linktree:- https://linktr.ee/anonymous4717 This query tracks the use of portable apps from known directories. There may be some false positive alerts since we’re also checking file names for the keyword ‘portable.’ Therefore, our analysts need to be careful.

4.2 Using SIEM Systems for Centralized Logging Security Information and Event Management (SIEM) tools, like Microsoft Sentinel, Splunk, or IBM QRadar, offer centralized logging for tracking portable apps across the network. SIEM systems collect and analyze data from endpoints, detecting suspicious activity such as processes executing from non-standard locations.

KQL Query for Process Monitoring: SecurityEvent | where EventID == 4688 | where ProcessCommandLine contains "E:\\\\\\\\" or ProcessCommandLine contains "F:\\\\\\\\" | project AccountName, ProcessCommandLine, TimeGenerated

This query can detect processes originating from removable media.

4.3 Real-Time Endpoint Detection and Response (EDR) Endpoint Detection and Response (EDR) solutions, like Microsoft Defender for Endpoint and CrowdStrike Falcon, continuously monitor all processes on devices. Administrators can configure custom rules to block portable applications based on their directory location, file hash, or signature. EDR Custom Rule Example: Block any .exe files from running in user profile directories or external drives (D:\\\\, E:\\\\).

4.4 Application Control via Group Policy Group Policy Objects (GPO) allow administrators to restrict the execution of unauthorized software through Software Restriction Policies (SRP) and AppLocker. AppLocker can block or allow specific applications based on file path, publisher, or file hash. Blocking executable files from running in non-standard directories, such as USB drives or Downloads folders, can effectively mitigate the risk posed by portable apps. GPO Configuration Example: Computer Configuration > Policies > Windows Settings > Security Settings > Software Restriction Policies > Additional Rules

4.5 Antivirus and Real-Time Monitoring Antivirus tools should be configured to scan all files from external drives and non-standard directories. Most antivirus programs can detect portable apps based on their behavior or inclusion in known malware databases. Administrators should ensure that removable drives are not excluded from real-time scans. PowerShell Command for Active Process Monitoring: Get-Process | Where-Object {$.Path -notlike "C:\\\\Program Files*" -and $.Path -notlike "C:\\\\Windows*"}

This script identifies processes running from unexpected locations.

5. Network-Level Detection 5.1 Network Traffic Monitoring Portable apps may initiate network connections to external servers or download additional components. Tools like Wireshark or Zeek can capture network traffic, helping administrators detect anomalies based on DNS queries or unauthorized connections originating from portable apps. 5.2 Auditing USB Usage Organizations should audit the use of external storage devices using GPO or endpoint management solutions. This helps track when USB drives are used and whether any unauthorized applications are executed from them. GPO Settings for USB Auditing: Computer Configuration > Administrative Templates > System > Removable Storage Access

6. User Education and Awareness A crucial aspect of mitigating the risks associated with portable apps is educating employees about security risks. Periodic training should cover the potential dangers of using unauthorized software and explain why running unapproved applications, including portable apps, can compromise network security.

7. Conclusion Portable applications, while convenient, introduce significant risks to enterprise security. Detecting these apps requires a multi-layered approach involving centralized logging, EDR tools, real-time antivirus protection, and proactive network monitoring. By implementing restrictions through Group Policy, AppLocker, and SIEM tools, organizations can mitigate the threat of unauthorized portable apps, ensuring a secure and compliant environment. Additionally, user education plays a key role in reducing the potential for employees to introduce these applications into the network.