necurs.exe

What is necurs.exe?

necurs.exe is a component of the Necurs botnet family. It functions as a downloader/loader that persists on infected Windows machines, contacting command-and-control servers to fetch additional payloads, plugins, and configuration updates. It often disguises itself within legitimate-looking startup or temp paths and is used to expand zombie computers for spam campaigns and distribution of further malware.

Necurs uses a modular downloader that fetches and executes payloads from C2s, often employing obfuscated traffic and domain- generation techniques to evade detection. It maintains persistence via registry keys and startup entries to survive reboots.

Types of Necurs Processes

• Loader Process: Initial necurs.exe instance that establishes persistence and contacts C2
• Downloader Module: Fetches additional malware payloads and updates from remote servers
• Persistence Helper: Registry and startup entries to survive reboots
• Network/Beacon Module: Maintains C2 communication and status reporting
• Cleanup/Anti-analysis Module: Attempts to hamper sandboxes and debugging environments
• Payload Loader: Executes downloaded malware components on the host

Is necurs.exe Safe?

No - necurs.exe is malicious and part of the Necurs botnet.

Is necurs.exe a Virus or Malware?

The real necurs.exe is malware. However, counterfeit files with the same name can appear; verify location and signature to confirm.

How to Tell if necurs.exe is Legitimate or Malware

1. File Location: Check for suspicious paths like C:\ProgramData\necurs.exe or C:\Users\Public\Documents\necurs.exe. Legitimate binaries are rarely placed in temp or user-writable folders.
2. Digital Signature: Right-click necurs.exe in its location -> Properties -> Digital Signatures. Should not show a trusted publisher; unsigned or unknown publisher is a red flag.
3. Resource Usage: Open Task Manager (Ctrl+Shift+Esc) and inspect necurs.exe. Unusually persistent high CPU/memory or constant network activity is suspicious.
4. Behavior: If necurs.exe launches submodules or connects to external hosts without user action, this indicates malicious activity.

Why Is necurs.exe Running on My PC?

necurs.exe runs as part of the Necurs botnet infrastructure to maintain control, download payloads, and communicate with C2 servers. It may persist after reboot to ensure continued operation.

Reasons it's running:

• Active Botnet Communication: The binary maintains beaconing to C2 servers, enabling remote control and payload delivery.
• Startup Persistence: Registry keys or startup folder entries ensure necurs.exe launches on boot.
• Downloader for Payloads: It fetches additional malware modules to expand reach and capabilities.
• Spam/Distribution Roles: Necurs components are used to coordinate spam campaigns and distribute further malware.
• Anti-analysis Evasion: Implements checks to avoid sandboxing and makes reverse engineering harder.

Can I Disable or Remove necurs.exe?

Yes – Stopping and removing the binary reduces risk, but a full cleanup is required to remove all components and persistence mechanisms.

How to Stop necurs.exe

• End Active Process: Open Task Manager (Ctrl+Shift+Esc), locate necurs.exe, and End Task.
• Terminate Startup Entries: Use Task Manager -> Startup tab to Disable suspicious entries related to necurs.
• Remove Scheduled Tasks: Open Task Scheduler and delete any Necurs-related tasks.
• Scan and Clean: Run a full system scan with updated antivirus/anti-malware tools and remove detected components.
• Network Cleanup: Block necurs communication by temporarily disabling network access or using firewall rules for known C2 domains.

How to Uninstall Necurs-Related Components

• ✔ Perform a full malware removal using reputable security software and ensure quarantine of all modules.
• ✔ Reset browser settings and remove any extensions installed by the malware.
• ✔ Update Windows and restore default security configurations.

Common Problems: Malware Persistence and Resource Use

If necurs.exe behaves suspiciously, you may see ongoing network activity, unexpected reboots, or elevated resource usage even after attempts to terminate the process.

Common Causes & Solutions

• Persistent startup entries: Remove registry Run keys and startup folder items associated with necurs; use Autoruns to identify and disable persistence hooks.
• Multiple payload modules: Identify and remove downloaded modules; perform a system-wide malware scan and clean residual components.
• Outdated security tooling: Update security software and definitions; run a deep scan with multiple reputable tools.
• Obfuscated binaries: Submit suspected files to malware analysis platforms for verification; avoid running unknown executables.
• Network beaconing: Block suspicious outbound connections via firewall rules; monitor network activity for domain generation algorithm patterns.
• Infected startup behavior: Reimage or perform a clean OS reinstall if persistent infections resist removal; ensure no recovery of malware via backups.

Related Processes