What happens when malware doesn’t go away even after you restart your system? When we talk about malware persistence, we’re referring to the tactics cyber attackers use to ensure their access to a system isn’t lost—even if you reboot the device, change passwords, or try to clean the system with antivirus software. In other words: they want to stay in your network no matter what.
How do they do it? By using various tricks that let them remain unnoticed, reactivate after a reboot, or even survive security tools that are supposed to remove them. Common techniques range from modifying system settings and injecting malicious code into legitimate processes to creating new user accounts without anyone noticing.
And here’s the worrying part: this often happens without you realizing it. Meanwhile, the attacker stays active in the background—stealing information, monitoring activity, or preparing even more severe attacks.
In this article, we’ll give you a clear understanding of how these persistence techniques work, what impact they can have, and how you can detect and block these actions with Wazuh before they turn into a serious problem.
To better understand how attackers operate, we’ll rely on the MITRE ATT&CK framework—a comprehensive database that documents the tactics and techniques used by real-world malicious actors. Here are some of the most common persistence techniques used to maintain access to compromised systems for as long as possible:
A very common way to maintain presence on a system is by scheduling automated tasks that execute malicious code at specific times or intervals—such as during system startup.
On Windows, the Task Scheduler is used.
On Linux, you’ll typically see changes in cron.
On macOS, attackers might use launchd.
A well-configured scheduled task can ensure malware is reactivated automatically without any user intervention.
Another effective technique is to exploit scripts that run when the system starts or when a user logs in. Malware slips into these scripts to guarantee it launches every time the system powers up.
For example:
On Linux, files like rc.local, directories like /etc/init.d/, or services configured with systemd are common targets.
In enterprise environments, group policies may also be leveraged to do this at scale.
The goal: run malicious code before the user even notices.
Processes that run with elevated privileges—like Windows services, Linux daemons, or macOS launch agents—are ideal for hiding malicious payloads.
Once an attacker manages to install or alter one of these services, they can execute their malware automatically whenever the machine starts or the system process launches. The scariest part is that, since these are legitimate processes, they don’t always raise alarms.
If an attacker gains sufficient access, they can simply create a new account on the system—locally, on the domain, or even in cloud services.
These accounts can be used to regain access unnoticed, especially if configured with admin privileges or disguised as system accounts. It’s a simple yet highly effective long-term persistence method.
In addition to creating new accounts, attackers can also modify existing ones. For example:
Changing passwords.
Adding users to higher-privilege groups.
Modifying files like ~/.ssh/authorized_keys to enable passwordless SSH access.
These changes often go unnoticed in many environments, especially if there’s no active monitoring system in place to detect them.
Because if an attacker manages to maintain persistence on your system, detecting the malware once isn’t enough. As long as the persistence methods remain, the attacker can keep coming back.
Here are some common consequences of ignoring this type of activity:
Long-term data leaks.
Unauthorized remote access.
Use of your systems as a launchpad for other attacks.
Damage to your company’s or brand’s reputation.
What’s more, many traditional antivirus solutions don’t detect these persistence methods, since they’re not always tied to malicious files—but rather to system configurations that look legitimate at first glance.
Read more: What is Incident Response in Cybersecurity?
If you're looking for a comprehensive solution to defend against these techniques, Wazuh is an excellent choice. It's a free and open-source platform that combines SIEM + XDR, giving you everything you need to monitor, detect, and respond to threats across different environments—on-premises, in the cloud, virtualized, or containerized.
Wazuh specifically helps with malware persistence through:
Wazuh doesn’t just detect anomalies—it can also respond to them automatically. Its active response module allows you to configure automatic actions based on specific events.
For example, if it detects:
A brute force attempt
The creation of an unauthorized account
A suspicious change in the registry or scheduled tasks
…it can execute a script to block IPs, disable accounts, or remove malicious files. All in real time, with no human intervention required.
Wazuh Active Response Disables a Linux Account Targeted by Brute Force Attacks
Real example: If an attacker tries to brute-force a login on a Linux account, Wazuh can automatically disable that account to prevent further access attempts.
Learn more about how Wazuh Active Response works:
The Wazuh FIM (File Integrity Monitoring) module acts like a silent guardian, keeping watch over key system files and directories. Its job is simple yet powerful: detect any unexpected changes and alert you immediately.
How does it work? First, FIM scans the files you're monitoring and creates a baseline—essentially a digital fingerprint of each file—using checksums and important attributes (like permissions or modification dates). From there, any change (creation, modification, or deletion) that doesn't match the original fingerprint triggers an alert.
This is especially useful when it comes to malware persistence, since many attacks attempt to modify startup scripts, system services, or critical configurations without raising suspicion.
Detection of Systemd Services and Timers Using the Wazuh FIM Module
Read more: Security and Regulatory Compliance with Wazuh
One of the pillars of keeping your systems secure is proper configuration. Often, security issues don’t stem from highly advanced malware but from poorly configured settings or unnecessary services that no one ever reviewed.
That’s where Wazuh’s SCA (Security Configuration Assessment) module comes in.
This module scans your endpoints for misconfigurations, unnecessary components, or insecure settings, and provides clear recommendations to fix them. It’s like an automatic security audit you can run anytime.
Wazuh SCA uses policy files (essentially a checklist of best practices) to review various system components, such as:
Operating system configurations
Critical files
Running processes
Registry keys (in Windows environments)
All of this helps identify settings that should be reviewed, adjusted, or hardened.
Here are some examples of issues SCA can help you identify:
Weak or outdated password policies
Unused software that poses a risk
Unnecessary services running in the background
Poorly secured network configurations
Insecure parameters in protocols like SSH or RDP
For example, if SSH logins are allowed without public key authentication, Wazuh will detect it and generate a clear alert—just like in the image below, where that specific flaw is flagged.
Wazuh SCA Scan Result Showing SSH Configuration
If there’s one thing that doesn’t lie in cybersecurity, it’s the logs. Every action, change, or event in your infrastructure leaves a trail. The key is knowing how to read it in time. That’s where Wazuh’s powerful log data analysis module comes into play.
This module gives you full visibility into what’s happening across your endpoints, network devices, and applications by collecting, analyzing, and storing logs in a centralized manner. With this information, you can detect threats, troubleshoot issues, perform compliance audits, and much more.
The Wazuh agent, installed on the systems you want to monitor, is responsible for:
Collecting system and application logs in real time
Sending that data to the Wazuh server for analysis and correlation
Generating automatic alerts when something abnormal is detected
This continuous flow of information helps you stay in control and make informed decisions before a problem turns into a security breach.
Malware persistence attempts
Creation of unauthorized accounts
Suspicious changes to registry keys
Modifications to system services
Critical errors or security failures
Unusual activity from users or applications
No matter how solid you think your system is—if there's an unpatched vulnerability, attackers will find it. That’s why one of the cornerstones of a strong security strategy is knowing exactly where those weak points are… before someone else exploits them.
Wazuh’s vulnerability detection module handles this for you.
How does it work? It’s simple: it scans the operating system and installed applications on your endpoints, then cross-references that data with known vulnerability databases (like those from its CTI platform). If it finds a match, it generates an automatic alert and displays it directly in the Wazuh dashboard.
A clear, centralized view of:
Which packages are vulnerable
Which operating system they’re on
Which agent is reporting it
How severe the vulnerability is (low, medium, critical)
All of this enables you to take proactive action—prioritizing patches and strengthening your systems before attackers can exploit those security gaps.
Wazuh Vulnerability Detection Dashboard
Malware persistence techniques are one of attackers’ favorite tools for staying inside a system for weeks or even months without being detected. This poses a significant risk to any organization.
Fighting them isn’t just about removing the malware. It requires a comprehensive strategy that includes:
Properly configured systems
Regular patching and updates
Continuous monitoring of files and accounts (FIM)
Active threat hunting
Full visibility into endpoint activity
If you’re looking for a robust solution to protect your infrastructure, TecnetOne can help you implement and customize Wazuh according to your organization’s specific needs.
Our team specializes in building tailored defense strategies for various environments—on-premises, cloud, hybrid, or containerized—ensuring complete and effective security coverage.
From the initial deployment and rule configuration to alert tuning and technical team training, we support you every step of the way to help you get the most out of Wazuh.