How to eliminate ApolloShadow malware from the operating system

What kind of malware is ApolloShadow?

ApolloShadow is the name of a malicious program that has been observed in cyber espionage campaigns. It is a custom-built malware used by a threat actor dubbed "Secret Blizzard". This group is believed to be a part of the FSB (Federal Security Service of the Russian Federation). Secret Blizzard has been linked with threat actors tracked as ATG26, Blue Python, Snake, Turla, Uroburos, VENOMOUS BEAR, Waterbug, and Wraith.

ApolloShadow malware has been used in ongoing campaigns that began at least in 2024. This activity targets diplomatic entities and other sensitive operations based in Moscow. It is not unlikely that ApolloShadow campaigns will expand.

ApolloShadow malware overview

ApolloShadow is a custom malware used by the Russian state-backed threat actor called "Secret Blizzard". Campaigns spreading this malware relied on the AiTM (Adversary-in-The-Middle) technique. AiTM is a method wherein the adversary places themself between two (or more) networks to facilitate following activity (such as delivering malware). This technique is not novel to Secret Blizzard, as this group has used similar tactics in older campaigns targeting Eastern European foreign ministries.

In the most recent ApolloShadow campaigns – which sought to compromise diplomatic entities, foreign embassies, and other high-sensitivity organizations in Moscow – the AiTM attack occurred at the ISP (Internet Service Provider) level.

To elaborate, the targeted device was placed behind a captive portal, and the Windows Test Connectivity Status Indicator service was run – yet instead of the browser opening the appropriate page, the victim was redirected to an attacker-controlled domain. As ApolloShadow's infection chain relies on the installation of a root certificate, it is highly likely that the opened website is intended to trick the user into installing it (e.g., by showing a certificate validation error). One of the known disguises for the root certificate was the Kaspersky Anti-Virus.

It is suspected that ApolloShadow infections allow for TLS/SSL stripping attacks – wherein browsers are forced to connect to websites by bypassing security measures like SSL encryption. In which case, the malware would be capable of accessing most of the victim's browsing activity, as well as certain tokens and credentials.

To expand upon how this campaign reaches the ISP level, the targeted entities used local Russian Internet/telecommunications services, and Secret Blizzard is a state-backed threat actor.

By downloading/installing the root certificate, the victim introduces ApolloShadow into the device. The malware begins its operations by collecting relevant device information, including network data and IP address.

This program seeks to gain admin privileges, and if the user account does not have them, the UAC (User Account Control) pop-up is displayed. This window asks the root certificate to be installed. In the observed attacks, the file-to-be-installed was named "CertificateDB.exe" and, as mentioned previously, was presented as the Kaspersky installation setup. The malware can display a pop-up claiming that certificates are being installed.

Upon successfully escalating the privileges, ApolloShadow enables the device to be discoverable on the network. It can also use one of two methods to weaken the firewall and allow file sharing. Chromium-based browsers accept ApolloShadow's certificate as trusted, while the malicious program has to modify preferences for the Mozilla Firefox browser to avoid certificate rejection.

Additionally, ApolloShadow creates a new admin user account (named "UpdatusUser" in the known infections) with an indefinite hardcoded password (without an expiration date) – and in this manner, the malware ensures persistent access.

ApolloShadow is used for cyber espionage, and the extent of the damage this malware can cause, especially since it can remain hidden for a significant amount of time, cannot be accurately quantified. Regardless, this malicious program poses serious threats, especially considering it is used in politically/geopolitically motivated attacks.

Examples of malware used in cyber espionage

We have written about thousands of malicious programs; Shadowpad, TONEINS, RomCom, and HyperBro are merely a few of our articles on ones that have been used in cyber espionage attacks.

Malware is a broad term that covers software that can have various malicious capabilities, ranging from data theft to file encryption for ransom demands.

Naturally, this software is widely used in attacks that have political and geopolitical motivations. However, the most prevalent reason is financial gain. Other motivations include process disruption (e.g., websites, services, companies, institutions, etc.), attackers seeking to amuse themselves or realize personal grudges, and hacktivism.

It must be emphasized that regardless of how malware operates or to what end it is used – the presence of this software on a system threatens device integrity and user safety. Therefore, all threats must be eliminated immediately upon detection.

How did ApolloShadow infiltrate my computer?

Entities of interest to the Secret Blizzard group that use local Russian ISP providers are incredibly vulnerable to the latest ApolloShadow campaign, which also combines social engineering tactics to facilitate the infection.

However, this malware could be spread using other techniques. Social engineering and phishing techniques are standard in malware proliferation.

In general, malicious software is distributed via backdoor/loader-type trojans, drive-by (stealthy/deceptive) downloads, untrustworthy download channels (e.g., unofficial and free file-hosting websites, Peer-to-Peer sharing networks, etc.), online scams, malicious attachments/links in spam (e.g., emails, PMs/DMs, social media posts, etc.), malvertising, illegal software activation tools ("cracks"), and fake updates.

Furthermore, some malicious programs can self-spread through local networks and removable storage devices (e.g., external hard drives, USB flash drives, etc.).

How to avoid installation of malware?

Due to the particular nature of ApolloShadow campaigns, the advice to lower the risks includes ensuring that network traffic is routed securely via an encrypted tunnel. The traffic has to be routed to a trustworthy network or VPN (Virtual Private Network) service that is not controlled or affiliated with potentially hostile third-parties.

Other general recommendations include researching software and downloading it only from official/verified sources. All programs must be activated and updated using legitimate functions/tools, as those obtained from third-parties can contain malware.

Additionally, we advise vigilance when browsing since the Internet is full of deceptive and malicious content. Incoming emails and other messages must be approached with care. Attachments or links present in suspicious/irrelevant mail must not be opened, as they can be virulent.

It is paramount to have a dependable antivirus installed and kept up-to-date. Security software must be used to run regular system scans and to remove detected threats. 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.

Screenshot of the pop-up displayed by ApolloShadow during installation:

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.

Tools you'll need

Combo Cleaner Antivirus 7-days free trial

Recommended primary scanner. VB100 certified. The 7-day free trial is available.

Microsoft Defender Offline Free · built-in

Built into Windows. Boots to a clean environment to catch rootkits.

Process Explorer Free

From Microsoft Sysinternals. Better than Task Manager - shows full paths and signatures.

Autoruns Free

From Microsoft Sysinternals. Lists every place malware can persist on your system.

Microsoft Safety Scanner (MSERT) Free

Official Microsoft on-demand scanner. Always-current signatures - expires every 10 days.

Phase 1~ 5 min

Contain - limit the damage

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1

Disconnect from the network

30 secNo tool needed

Unplug your Ethernet cable and turn off Wi-Fi. If you're on a laptop, the airplane-mode key works fastest.

Why this matters

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.

2

Boot into Safe Mode with Networking

3 min

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.

Windows 11

Open Settings → System → Recovery. Click Restart now next to Advanced startup.

Your computer will restart into the "Choose an option" menu. Click Troubleshoot → Advanced options → Startup Settings → Restart. After the second reboot, press 5 or F5.

Windows 10

Click the Windows logo, hold Shift, click the Power icon and choose Restart. In the Choose an option screen, click Troubleshoot → Advanced options → Startup Settings → Restart. 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.

Phase 2~ 15 min

Identify - find what's hiding

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3

Inspect running processes with Process Explorer

Tool: Process Explorer5 min

Download Process Explorer from Microsoft Sysinternals. Run it as Administrator. Click Options → Verify Image Signatures and View → Lower Pane View → DLLs.

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.

Why not just Task Manager

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.

4

Map every persistence point with Autoruns

Tool: Autoruns 14.x10 min

Download Autoruns. Right-click Autoruns.exe and choose Run as administrator - without elevation, Autoruns can't inspect protected registry hives.

In the menu, open Options → Hide Microsoft Entries and Options → Hide Empty Locations, 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

Pro tip

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.

5

Check the hosts file and DNS settings

3 minBuilt into Windows

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 Settings → Network & internet → [your adapter] → DNS server assignment and verify both DNS and DNS over HTTPS (DoH) settings haven't been hijacked.

Why this matters

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.

Phase 3~ 60-90 min

Remove - three scans, one cleanup

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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.

6

Run Microsoft Defender Offline

Tool: Built into Windows15 min

Reboot to normal Windows. Open Windows Security → Virus & threat protection → Scan options. 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.

Why this comes first

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.

Recommended antivirus

Combo Cleaner

VB100 certified. Includes anti-trojan, registry/persistence scanning, anti-spyware in one pass. The 7-day free trial is available.

Download Combo Cleaner

7

Run Combo Cleaner full system scan

Tool: Combo Cleaner20-40 min

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.

8

Run Microsoft Safety Scanner as a second-opinion scan

Tool: Microsoft Safety Scanner15 min

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.

Why a second scan

Different scanning engines catch different threats. Running an additional Microsoft scan after Combo Cleaner is the single most underused verification step in malware removal.

9

Manually remove anything still listed in Autoruns

Tool: Autoruns10 min

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.

Important

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).

Phase 4~ 15 min

Recover - restore browsers and security

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10

Reset browsers and clear notification permissions

5 min

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/reset and click "Restore settings to their original defaults." Then visit chrome://settings/content/notifications and remove any unfamiliar sites.
• Edge: visit edge://settings/reset. Then check edge://settings/content/notifications.
• Firefox: open about:support and 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.

11

Re-enable Defender, Tamper Protection, and update everything

10 min

Many trojans disable security software. Open Windows Security → Virus & threat protection → Manage settings 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 (Settings → Windows Update → Check for updates) and update your browsers and applications. The infection vector that let the trojan in originally usually involves outdated software.

Phase 5~ 15 min + 7 days

Verify & secure

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12

Change passwords from a clean device

20 min⚠ Critical

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:

1. Primary email first - it's the recovery hub for everything else
2. Banking and financial accounts
3. Password manager master password (if you use one)
4. 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.

13

Verify the clean and monitor for 7 days

5 min + 1 week monitoring

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 Settings → System → Recovery → Reset this PC → Remove everything → Cloud download. 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 ApolloShadow malware, should I format my storage device to get rid of it?

Malware removal rarely requires such drastic measures.

What are the biggest issues that ApolloShadow malware can cause?

The dangers associated with an infection depend on a malicious program's abilities and the attackers' goals. ApolloShadow is a custom malware used by a Russian state-backed threat actor dubbed "Secret Blizzard". It has been utilized to target embassies and diplomatic entities based in Moscow. Cyber espionage attacks of this kind carry even more risks than those posed by high-risk malware, such as severe privacy issues, financial losses, and identity theft.

What is the purpose of ApolloShadow malware?

As mentioned above, ApolloShadow has been used for cyber espionage. However, politically and geopolitically motivated attacks are not the only type. Profit is the most common reason behind malware infections, but malicious software is also used for amusement, realization of personal vendettas, process disruption (e.g., sites, services, companies, etc.), and hacktivism.

How did ApolloShadow malware infiltrate my computer?

In the latest campaigns, ApolloShadow infiltration chain relied on the AiTM technique at the ISP level; thus, victims using local Russian ISPs were particularly vulnerable.

Generally, the most widely used malware proliferation methods include: drive-by downloads, trojans, spam mail, malvertising, online scams, dubious download channels (e.g., freeware and free file-hosting websites, Peer-to-Peer sharing networks, etc.), fake updaters, and illegal software activation ("cracking") tools. Some malicious programs can self-spread through local networks and removable storage devices.

Will Combo Cleaner protect me from malware?

Combo Cleaner is designed to scan systems and eliminate all manner of threats. It is capable of detecting and removing most of the known malware infections. Note that performing a complete system scan is essential since sophisticated malicious programs tend to hide deep within systems.