After a ransomware attack, the hard drives of a company server are encrypted, all data appears to be lost – but for the digital forensic experts at the State Criminal Police Office, the work is just beginning. Using highly specialized tools and years of experience, they reconstruct deleted files, establish connections to darknet marketplaces and track the digital footprints that the attacker inevitably leaves behind. What was science fiction just a few decades ago is now part of everyday life in crime fighting: digital forensics has developed into an indispensable tool for countering the increasingly complex threats from cyberspace.
1. What is digital forensics?
Digital forensics refers to the systematic process of identifying, collecting, analyzing and documenting digital evidence. The goal is essentially the same as that of our analog colleagues: to secure evidence in court that can help solve crimes. Unlike classic forensics, where the focus is on fingerprints or DNA traces, this is about data traces
The beginnings of digital forensics date back to the 1980s, when computers were first used on a significant scale for criminal activities. What began with comparatively simple data recovery methods has developed into a highly complex discipline that must constantly keep up with the latest technology.
Three basic principles are non-negotiable:
- The complete chain of evidence (“Chain-of-Custody”): Every step in the handling of digital evidence must be documented to prove that no manipulation has taken place.
- The integrity of the evidence: Digital evidence must be secured so that it remains unchanged – typically through the creation of forensic copies and the use of write blockers.
- Systematic approach: Only recognized methods and tools are used to ensure the reproducibility of the results.
The legal framework for this work is complex and includes, in addition to the criminal procedure code, data protection laws and international agreements to combat cybercrime.
2. The current threat landscape
Even if in 2025 the number of financially motivated cyber attacks will probably decrease slightly for the first time in a long time – a development that can be attributed primarily to successful international investigations, in which the BKA (Federal Criminal Police Office) and BSI (Federal Office for Information Security) were significantly involved – the situation still remains tense. The current BSI annual report shows that the number of new vulnerabilities discovered every day has increased by 24%. What is particularly worrying, however, is the increasing professionalization of perpetrator structures.
What was once the work of individual “hackers” is now a thriving business model: “Cybercrime-as-a-Service” (CaaS). In this ecosystem, specialized actors offer their services – from the developer of the malware to the operator of the infrastructure to the “money launderer” who converts cryptocurrencies into cash.
The increasing use of artificial intelligence is particularly worrying. Tools like WormGPT – a language model based on the GPTJ model that has been optimized for criminal purposes – make it possible to create deceptively genuine phishing emails and deepfakes in unlimited quantities within a very short time.
The perpetrator groups often operate from “safe havens” – states that do not cooperate with Western law enforcement authorities. This makes investigative work even more difficult and makes international cooperation even more important.
3. Specialized branches of digital forensics
With the increasing complexity of digital systems, forensics has also become more specialized. The most important branches:
- Computer Forensics/Cyber Forensics: The classic area that deals with the examination of desktop PCs, laptops and servers. The focus of the analyzes are hard drives, RAM and operating system components.
- Mobile device forensics: Smartphones and tablets require special methods because they use different operating systems and storage technologies. Particular challenges arise, among other things, from the major role that encryption plays in this area.
- Database forensics: Large amounts of data are stored in databases – analyzing them requires specialized knowledge of database structures and SQL query languages.
- Network forensics: The focus here is on analyzing data traffic. Network forensic experts examine log files, packet captures and firewall logs to reconstruct attack paths.
- File system forensics: Every operating system organizes data differently. Specialists in this area understand the structures of NTFS (Windows), ext4 (Linux) or APFS (Apple) and can reconstruct information even from seemingly deleted areas.
These specializations often overlap in practice, and complex cases require the collaboration of different experts.
4. Methods of digital search for traces
Digital forensics methods can be divided into two main categories:
Offline forensics
The classic approach: The system is offline and 1:1 copies of all disks are created. These copies – not the originals – are then analyzed. Advantages:
- No risk of altering evidence
- Opportunity to try out different analysis techniques
- Reproducibility of results
Work on a new case always starts with a forensic backup, i.e. creating an exact copy of all digital data without changing the original. In the second step, the data material is prepared and, if necessary, reconstructed. The methods used are diverse and are similar to the techniques used in the professional data recovery are used:
- Carving techniques: Even if the directory structure is destroyed, files can be reconstructed using characteristic signatures.
- Steganography detection: Hidden data in images or audio files can be discovered.
- Timestamp analysis: The chronology of events can be reconstructed by examining metadata.
- Registry analysis: On Windows systems, the registry provides valuable information about installed programs, user activities and system configurations.
A particular focus is on the analysis of communication data. Even if messages have been encrypted or deleted, metadata (who communicated with whom and when) can provide valuable clues.
Online forensics
With online forensics, the system under investigation is analyzed during ongoing operation. This is particularly necessary when so-called volatile data needs to be backed up:
- Contents of the main memory (RAM)
- Running processes and open network connections
- Encrypted data accessible when unlocked
The challenge: Every forensic intervention changes the system itself. Special tools with a minimal “footprint” help to minimize these changes.
5. The future of digital forensics
Two crucial factors for the development of digital forensics in the next few years will be the training of qualified specialists and new forms of international cooperation.
The Training of specialists becomes a critical factor. Become on online job boards IT forensics and data rescuer increasingly in demand. Universities and colleges have responded and are offering specialized courses of study. At the same time, continuous training is essential as technologies are constantly evolving.
International cooperation will have to be intensified and partly rethought against the background of the increasing internationalization of cyber crime. Initiatives such as the Council of Europe’s “Convention on Cybercrime” create a legal framework for cross-border investigations. Organizations such as Europol and Interpol coordinate international operations against cybercriminals.
Of course, it is above all the rapid technical development that will present digital forensic experts with new challenges.
Encryption: Modern encryption methods are practically impossible to crack. Forensic scientists must find alternative ways to access the data – for example by analyzing memory images in which keys could be temporarily unencrypted.
Amounts of data: The amount of data to be examined is growing exponentially. An average case today can already contain several terabytes. One way to address this development is to use artificial intelligence and machine learning to identify relevant data.
Cloud computing: When data is increasingly no longer stored locally but in the cloud, complex legal questions arise in addition to technical challenges.
Anti-forensics: Criminals are developing targeted techniques to make forensic investigations more difficult – from self-deleting programs to systems that automatically destroy data when a forensic analysis is detected.
Digital forensics is developing into a central link between the digital world of data and the analogue world of law. Their methods are constantly evolving – in a race with increasingly sophisticated attack techniques.
Today, if a company falls victim to a cyberattack, the chances are better than ever that digital forensics experts will be able to identify the perpetrators. Even in the digital space, every criminal activity leaves traces. You just have to know how to find and evaluate these traces.
12/04/2025