Get free scan and check if your device is infected.
Remove it nowTo use full-featured product, you have to purchase a license for Combo Cleaner. Seven days free trial available. Combo Cleaner is owned and operated by RCS LT, the parent company of PCRisk.com.
What kind of malware is PNGPlug?
PNGPlug is a malware loader used in attacks targeting Chinese-speaking regions (such as Hong Kong, Taiwan, and mainland China). These campaigns often start with phishing websites designed to deceive users into running a malicious Microsoft Installer (MSI) package camouflaged as legitimate software.
More about PNGPlug
When the installer with PNGPlug is run, it installs a harmless-looking app to avoid suspicion while also extracting an encrypted file that hides the malware. A key part of this malware is a file called "libcef.dll", which acts as the loader and prepares the system for the malware to run.
PNGPlug changes system files to inject malicious code into memory, deciding its actions based on specific instructions. To hide its malicious code, PNGPlug uses fake .png files, like aut.png and view.png. These files look harmless but contain malware that the loader injects into memory, helping it run unnoticed.
PNGPlug's primary purpose is to deliver ValleyRAT, a Remote Access Trojan (RAT). This RAT uses shellcode execution, obfuscation, and privilege escalation to stay active and maintain control over compromised systems.
ValleyRAT can drop and execute files, including additional malware like ransomware or cryptocurrency miners, ensuring its persistence by setting itself to run at system startup. Also, the malware gathers system information, such as running processes, and can adapt its behavior by stopping or restarting itself.
These capabilities allow it to infiltrate, persist, and manipulate infected systems, making it a significant threat to victims.
| Name | PNGPlug malware loader |
| Threat Type | Malware Loader |
| Detection Names | Antiy-AVL (GrayWare/Win32.Wacapew), Combo Cleaner (Trojan.GenericKD.74346373), ESET-NOD32 (Multiple Detections), Rising (Malware.SwollenFile!1.E38A (CLASSIC)), Symantec (Trojan Horse), Full List (VirusTotal) |
| Payload | ValleyRAT |
| Symptoms | Loaders are often designed to stealthily infiltrate the victim's computer and remain silent, and thus no particular symptoms are clearly visible on an infected machine. |
| Distribution methods | Phishing websites, malicious installers, infected email attachments, malicious online advertisements, social engineering, software 'cracks'. |
| Potential Damage | Additional infections, stolen passwords and banking information, identity theft, monetary loss. |
| Malware Removal (Windows) |
To eliminate possible malware infections, scan your computer with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. Download Combo CleanerTo use full-featured product, you have to purchase a license for Combo Cleaner. 7 days free trial available. Combo Cleaner is owned and operated by RCS LT, the parent company of PCRisk.com. |
Conclusion
Malware like PNGPlug shows how cyber threats are becoming more advanced, using clever tactics to stay hidden while delivering harmful payloads like ValleyRAT. These threats can take control of systems and carry out various malicious actions, emphasizing the need for strong security to protect against them.
Other examples of malware categorized as loaders include Venom, GodLoader, and JinxLoader.
How did PNGPlug infiltrate my computer?
Computers get infected with PNGPlug when users fall for phishing websites that trick them into downloading a malicious MSI package disguised as legitimate software. Once the package is run, it installs a seemingly harmless app to avoid suspicion while secretly extracting an encrypted file containing the malware.
Other methods often used to deliver malware include sending phishing emails containing malicious links or attachments, exploiting software vulnerabilities, crafting malicious advertisements, spreading technical support scams, hiding malware in pirated software, and using P2P networks, third-party downloaders, and similar channels.
How to avoid installation of malware?
Be cautious when downloading files and get software from trusted sources, such as official websites or app stores. Avoid clicking links or opening attachments in unsolicited emails or messages from unknown senders. Keep your operating system and security software up to date, and use a reliable security tool.
Additionally, do not trust advertisements, pop-ups, and other content on dubious web pages, and regularly scan your system for malware. If you believe that your computer is already infected, we recommend running a scan with Combo Cleaner Antivirus for Windows to automatically eliminate infiltrated malware.
How to remove malware manually?
Most trojan infections can be removed by running a full system scan with Combo Cleaner. The full manual procedure below is for cases where automatic removal failed, where you want to verify a scan caught everything, or where the threat has multiple persistence points.
Disconnect from the network
Unplug your Ethernet cable and turn off Wi-Fi. If you're on a laptop, the airplane-mode key works fastest.
Many trojans exfiltrate data - saved browser passwords, banking sessions, screenshots - and accept remote commands. Cutting the network stops both immediately. Keep it disconnected until Phase 4.
Boot into Safe Mode with Networking
Safe Mode loads a minimal set of drivers and stops most malware from auto-running. "With Networking" lets you download tools - re-enable Wi-Fi only after you've booted in.
Open . Click Restart now next to Advanced startup.
Your computer will restart into the "Choose an option" menu. Click . After the second reboot, press 5 or F5.
Click the Windows logo, hold Shift, click the Power icon and choose Restart. In the Choose an option screen, click . Press F5.
Windows 8
Go to the Start Screen, type Advanced, select Settings → Advanced startup options → Restart now → Troubleshoot → Advanced options → Startup settings → Restart → F5.
Note: Windows 8 reached end-of-life in January 2023 - running on it puts you at much higher risk of reinfection.
Windows 7
Click Start → Shut Down → Restart → OK. As the system boots, press F8 repeatedly until the Windows Advanced Options menu appears, then choose Safe Mode with Networking.
Note: Windows 7 reached end-of-life in January 2020 - running on it puts you at much higher risk of reinfection.
Inspect running processes with Process Explorer
Download Process Explorer from Microsoft Sysinternals. Run it as Administrator. Click and .
Sort by "Verified Signer." Anything unsigned running from %AppData%, %LocalAppData%, %Temp%, or %ProgramData% is suspicious. Right-click → Properties to see the full image path. Right-click → "Search Online" to look up unfamiliar process names.
Task Manager hides full file paths, doesn't show digital signatures, and groups processes in ways that make malware easy to miss. Process Explorer is the same tool Microsoft engineers use.
Map every persistence point with Autoruns
Download Autoruns. Right-click Autoruns.exe and choose Run as administrator - without elevation, Autoruns can't inspect protected registry hives.
In the menu, open and , then click Refresh.
Modern trojans don't just live in startup. Walk through these tabs and look for unsigned or unfamiliar entries:
- Logon - classic Run/RunOnce keys
- Scheduled Tasks - frequent hiding spot, especially tasks with PowerShell, MSHTA, or rundll32 actions
- Services - unsigned services in non-Microsoft folders
- WMI - Event Subscriptions are a stealthy persistence mechanism (MITRE T1546.003)
- Image Hijacks - Image File Execution Options "Debugger" abuse
- AppInit - DLLs loaded into every GUI process
- Browser plug-ins - unsigned add-ons across all installed browsers
Right-click any suspicious entry → "Jump to Image" to see the actual file. Right-click → "Search Online" opens VirusTotal for the file hash. Don't delete yet - just write down the file paths and entry names. We'll remove them after the scans.
Check the hosts file and DNS settings
Trojans often redirect bank, antivirus, and update domains to attacker-controlled servers by editing the hosts file or DNS settings.
Hosts file: Open Notepad as Administrator and open C:\Windows\System32\drivers\etc\hosts. Legitimate entries are commented with #. Any uncommented IP-to-domain mapping is suspicious - especially redirects for microsoft.com, windowsupdate, or your bank.
DNS settings: Open Command Prompt as Administrator and run ipconfig /all. Confirm your DNS servers point to your ISP, your router, or a known public resolver (Cloudflare 1.1.1.1, Google 8.8.8.8). Then open and verify both DNS and DNS over HTTPS (DoH) settings haven't been hijacked.
A clean PC with hijacked DNS is still a compromised PC. You'll think you're at chase.com and you'll be at the attacker's clone.
No single antivirus catches everything. The order below is intentional: offline scan first (catches rootkits before Windows fully loads), then on-demand scanners on the running system, then manual cleanup of anything they missed.
Run Microsoft Defender Offline
Reboot to normal Windows. Open . Select Microsoft Defender Antivirus (offline scan) and click Scan now. Your computer will restart into a stripped-down environment and scan before the full operating system loads.
Rootkits and bootkits hide from any scanner running on the same Windows session that's already infected. A pre-boot offline scan sees the disk before the malware can hide itself.
VB100 certified. Includes anti-trojan, registry/persistence scanning, anti-spyware in one pass. The 7-day free trial is available.
Download Combo CleanerRun Combo Cleaner full system scan
Install Combo Cleaner and run a full system scan (not the quick scan). Let it complete fully, review the detected threats, and apply the recommended actions. Combo Cleaner will quarantine known trojans and registry persistence.
Run Microsoft Safety Scanner as a second-opinion scan
Download Microsoft Safety Scanner (MSERT.exe), Microsoft's free on-demand tool. The binary expires every 10 days, which means every download has the latest signatures. Run a full scan after Combo Cleaner to catch anything one engine alone might miss.
Different scanning engines catch different threats. Running an additional Microsoft scan after Combo Cleaner is the single most underused verification step in malware removal.
Manually remove anything still listed in Autoruns
Reopen Autoruns. Anything you flagged in Step 4 that's still present hasn't been caught by the automated scans. For each remaining suspicious entry: right-click → Delete in Autoruns (this removes the persistence registration), then navigate to the file path and delete the actual file. Empty the Recycle Bin.
Some malware files reappear after deletion because something else on the system recreates them. If you delete a file and it returns within minutes, you have a remaining persistence point that Autoruns didn't show - usually a service or scheduled task running under SYSTEM. Re-run the scans from Steps 6-8 or proceed to a clean install (see end of guide).
Reset browsers and clear notification permissions
Trojans and adware frequently hijack browsers - change the default search engine, install rogue extensions, or grant themselves notification permissions to keep displaying scam pop-ups even after the malware is gone.
- Chrome: visit
chrome://settings/resetand click "Restore settings to their original defaults." Then visitchrome://settings/content/notificationsand remove any unfamiliar sites. - Edge: visit
edge://settings/reset. Then checkedge://settings/content/notifications. - Firefox: open
about:supportand click Refresh Firefox (Firefox uses "Refresh," not "Reset"). Then check Settings → Privacy & Security → Permissions → Notifications.
Review installed extensions in each browser and remove anything you don't recognize, especially extensions you didn't install yourself.
Re-enable Defender, Tamper Protection, and update everything
Many trojans disable security software. Open and confirm Real-time protection, Cloud-delivered protection, and Tamper Protection are all turned on. Tamper Protection prevents malware from disabling Defender silently.
Then run Windows Update () and update your browsers and applications. The infection vector that let the trojan in originally usually involves outdated software.
Change passwords from a clean device
If the trojan was an info-stealer (Lumma, RedLine, Vidar, and similar are extremely common), assume every password saved in your browser is compromised. Change them from a different, known-clean device - your phone is fine if it's not infected.
Recommended order:
- Primary email first - it's the recovery hub for everything else
- Banking and financial accounts
- Password manager master password (if you use one)
- Social media, shopping, and remaining accounts
Where available, enable phishing-resistant multi-factor authentication (passkeys / FIDO2 hardware keys / authenticator apps) - SMS-based MFA is bypassable by sophisticated attackers.
Verify the clean and monitor for 7 days
Reconnect to the network and run one final full scan with Combo Cleaner. Open Task Manager (Ctrl + Shift + Esc) and switch to the Startup apps tab - confirm nothing suspicious has reappeared.
Over the next 7 days, watch for symptom recurrence: unexpected high CPU usage, unknown processes returning, browser redirects, or pop-ups. If anything returns, you missed a persistence point and the procedure needs to be repeated - or you may have a deeper compromise that requires a clean install.
When to clean install Windows instead
Manual removal isn't always the right answer. Reinstalling Windows from scratch is the only way to be 100% certain when:
- The malware reappears after every removal attempt
- A bootkit or UEFI rootkit was detected (this class of threat sits below the operating system and survives a normal Windows reinstall)
- A confirmed credential-theft trojan ran with administrator privileges (Lumma, RedLine, Vidar) - the system likely has multiple unknown payloads
- The PC is used for online banking, business email, or anything where partial doubt isn't acceptable
A clean install is a 30-60 minute process: Windows 11 reinstall via . Back up documents to external storage first, scan the backup with Combo Cleaner before restoring it, and reinstall applications fresh - never restore them from a backup of the infected system.
Important: Manual removal requires advanced computer skills. If you're not confident identifying system files from malicious files, run an automated scan with Combo Cleaner and Windows Defender and stop there - that path catches the vast majority of consumer trojans without the risk of breaking Windows by deleting the wrong file.
Frequently Asked Questions (FAQ)
My computer is infected with PNGPlug malware, should I format my storage device to get rid of it?
It is advisable to use a trusted malware removal tool to scan and clean the system. Formatting a storage device removes all data (including malware).
What are the biggest issues that malware can cause?
Malware can lead to various serious consequences, including unauthorized data access, damage to systems, financial losses, disruptions to the operating system, and the spread of additional infections.
What is the purpose of PNGPlug?
PNGPlug is primarily designed as a malware loader, delivering and executing additional malicious payloads, such as ValleyRAT.
How did PNGPlug infiltrate my computer?
PNGPlug likely infiltrated your computer through a phishing website that tricked you into downloading a malicious MSI package. Once executed, the package installs a harmless-looking app while extracting the malware.
Will Combo Cleaner protect me from malware?
Combo Cleaner will scan your system and remove detected threats. This tool is capable of identifying most known malware. However, advanced malware often hides deeply within the system, so it is crucial to perform a full system scan to ensure detection and removal.
Share:
Facebook
X.com
LinkedIn
Copy Link
Tomas Meskauskas
Expert security researcher, professional malware analyst
I am passionate about computer security and technology. I have an experience of over 10 years working in various companies related to computer technical issue solving and Internet security. I have been working as an author and editor for pcrisk.com since 2010. Follow me on Twitter and LinkedIn to stay informed about the latest online security threats.
PCrisk security portal is brought by a company RCS LT.
Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.
Our malware removal guides are free. However, if you want to support us you can send us a donation.
DonatePCrisk security portal is brought by a company RCS LT.
Joined forces of security researchers help educate computer users about the latest online security threats. More information about the company RCS LT.
Our malware removal guides are free. However, if you want to support us you can send us a donation.
Donate
▼ Show Discussion