Malware analysis

What is malware?

Malware is an abbreviation for “malicious software”. It is software that has been developed to damage, disrupt or control computers, networks or devices. The most common types of malware include

• Viruses: Programs that attach themselves to legitimate files and spread when these files are executed.
• Worms: Self-replicating programs that spread via networks without requiring user interaction.
• Trojans: Malware that disguises itself as useful software but performs harmful actions when executed.
• Ransomware: Malware that encrypts files or systems and demands payment to restore access.
• Spyware: Software that secretly collects information about users without their knowledge.
• Adware: Malware that displays unwanted advertising on a device.

How does malware analysis work?

Malware analysis is used to understand how malware works. It is divided into two main categories:

• Static analysis: Examines the malware code without executing it. This includes analyzing binary files, disassembling (reverting machine code to source code) and searching for suspicious strings. The advantage is that this is done in a secure environment.
• Dynamic analysis: Executes the malware in a controlled environment (e.g. a sandbox) to observe its behavior. This checks which files the malware creates or modifies, which network connections it establishes and which other malicious activities it carries out.

Advanced analysis can also include debugging techniques, memory dump analysis and reverse engineering (with tools such as IDA Pro).

Why is malware analysis important?

Malware analysis is an essential part of cyber security as it enables threats to be understood and effective countermeasures to be developed. By analyzing malware, security researchers can:

• Create signatures to detect malware more quickly in the future.
• Identify vulnerabilities in systems that are exploited by malware.
• Develop defense strategies to prevent further infections.
• Reverse malware infections or minimize their damage.

Without malware analysis, it would take much longer to detect and respond to new threats.

Which tools are used for malware analysis?

There are a variety of tools that are used to analyze malware, depending on the type of analysis (static or dynamic). Among the best known are

• IDA Pro: A powerful disassembly and debugging tool that converts machine code into a readable form.
• Ghidra: An open source disassembler developed by the NSA. Similar to IDA Pro.
• Wireshark: A network analysis tool used to monitor and analyze network activity to detect malicious traffic.
• Process Monitor (ProcMon): Monitors the processes on a system in real time and shows which files and registry keys are being processed by the malware.
• Cuckoo Sandbox: An open source tool that executes malware in an isolated environment and analyzes the malware’s behavior.
• YARA: A tool for identifying and classifying malware based on patterns or rules.

What is the difference between static and dynamic analysis?

• Static analysis: This involves analyzing the malware code without executing it. The aim is to understand the structure and function of the malware by analyzing the binary code. This is often done by disassembling or decompiling it. Advantages: Safer, as the malware is not actually executed. Disadvantages: Limited results as packing or obfuscated malware is more difficult to analyze.
• Dynamic analysis: The malware is actually executed in an isolated environment (e.g. in a sandbox). This makes it possible to observe which activities it performs on the system (e.g. which files it creates, which network connections it establishes).advantages: Direct observation of malware behavior. Disadvantages: More risky as the malware is executed (if not in a secure environment).

How can you protect yourself against malware?

Several measures should be taken to protect against malware, including:

• Updating software: Keep operating systems and software up to date to close security gaps that can be exploited by malware.
• Use reliable antivirus software: Antivirus programs can detect and block malware before it causes damage.
• Security guidelines: Implement and follow strict security policies, such as avoiding unsafe websites and clicking on unknown links or attachments.
• Backup: Make regular backups of important data, especially to protect against ransomware.
• Email security: Be careful with email attachments and links. Phishing emails are a common way in which malware is spread.
• Firewalls and network security: Use firewalls and monitor network traffic for suspicious activity.

How do you recognize that a system is infected with malware?

Typical signs of a malware infection are

• Slow system performance: Malware can use system resources, resulting in a slowdown.
• Pop-ups and unwanted ads: Sudden ads or pop-ups that you weren’t expecting can indicate a malware infection.
• Unusual network traffic: Increased or unexpected network activity could indicate that malware is trying to send or receive data.
• Program crashes or malfunctions: Applications crash or behave strangely.
• Unknown processes in the Task Manager: Check the Task Manager for unknown or suspicious processes that are running.

What is the first step to take if you suspect that malware is in the system?

If you suspect that your system is infected:

1. Disconnect the device from the network to prevent further spread.
2. Perform a malware scan with updated antivirus software.
3. Investigate suspicious processes and applications manually, especially those that are unknown.
4. If possible, perform a system restore to restore the system to a previous state.
5. If the threat is more serious, consider reinstalling the system.

How is malware reversed or removed?

• Antivirus software: Modern antivirus programs can detect and remove many types of malware.
• Manual removal: Some malware requires manual removal by deleting suspicious files, registry entries and processes.
• Reinstalling the system: In serious cases, it may be necessary to reinstall the entire system and restore data from a backup.

Can malware exploit unrecognized security vulnerabilities?

Yes, malware can exploit so-called zero-day exploits, i.e. vulnerabilities that are not yet known or for which no security updates exist yet. This type of attack is particularly dangerous as there are often no defenses in place before the vulnerability is discovered and patched.

How long does it take to analyze malware?

The duration depends on the complexity of the malware. A simple malware can be analyzed in a few hours, while more advanced, obfuscated or polymorphic malware can take several days to weeks. Reverse engineering is often the most time-consuming part.

What role do signatures play in the detection of malware?

Signatures are patterns found in malware samples that help detect similar threats in the future. Antivirus programs compare files and activities against these signatures to identify malware. However, signatures only work against known malware, which is why they need to be supplemented by heuristic analysis and machine learning to detect new or unknown threats.

What is “sandboxing” in malware analysis?

Sandboxing refers to the execution of malware in an isolated, virtual environment in order to observe how it behaves without endangering the real system. This is a crucial step in dynamic analysis, as it allows the behavior of the malware (e.g. file changes, network traffic) to be analyzed in real time.

What do malware analysts do to identify new threats?

Analysts use a combination of:

• Threat Intelligence: Monitoring of threat databases and security forums.
• Behavioral analysis: Monitoring of unusual system and network behavior.
• Reverse engineering: Detailed investigation of suspicious files.
• Machine learning: Use of algorithms to recognize patterns in new malware variants.

How do you stay up to date with the latest malware threats?

Malware analysts and security experts use various resources to find out about current threats:

• Security blogs and forums (e.g. KrebsOnSecurity, BleepingComputer)
• Threat intelligence platforms (e.g. VirusTotal, ThreatConnect)
• Cybersecurity conferences (e.g. Black Hat, DEF CON)
• Social media (Twitter is an important source of real-time information)

What are malware “samples” and how do you get them for testing?

Malware samples are copies of real malware that are used for analysis purposes. Analysts can obtain these from platforms such as VirusTotal, Hybrid Analysis or via honeypots, which are designed to capture malware in an isolated environment.

Zurück zur Übersicht des Glossars