PE-bear: The Art of Intuitive Malware Analysis

PE-bear: The Art of Intuitive Malware Analysis

How Visual Design Turns the ‘First View’ into Actionable Insights for Reverse Engineering

 

 

“To understand the immeasurable, the mind must be extraordinarily quiet, still.”
— Jiddu Krishnamurti

 

Seeker(李标明) · @clibm079    

China · Independent Malware Analyst & Researcher 

From 2025.11.14 to 2025.11.21

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Prologue: document the insights I gained

Last time, I published an article titled “Revisiting SubVirt & Blue Pill: From Attacker Proof-of-Concepts to Defensive Foundations.” Somewhere along the way, I noticed my hair turning gray faster than expected—a reminder of the pressure that comes with this path, and something I’ve gradually learned to manage.

 

In the world of malware research, I sometimes feel like a mountaineer: constantly climbing, constantly adapting, and always facing the next challenging peak.

Recently, I shared several short videos on X while exploring the internals of PE-bear. I did not follow any tutorials—my goal was to understand the tool from first principles. During this process, I found PE-bear to be not only efficient and subtle but also elegantly designed with hidden advanced features. Yes, it doesn’t offer much information about its functions—which is unusual—but it’s amazing, and it speaks for itself.

This exploration generated not only texts, images, and videos but also observation, thinking, views, and reflection, which helped me build the foundation of understanding, and it eventually inspired and encouraged me to write this article and document the insights I gained. These notes have become a meaningful part of my ongoing malware research journey.

 

What makes one become curious about the world?

The thing itself is interesting enough and makes one feel good, I think.

When one learns more and masters it well, the strength generates on the exploring journey.

 

First Impression: A Clean and Thoughtfully Designed Interface

To be honest, the first time I opened PE-bear, it was beautiful, which engraved a strong and immediate impression. Its elegance and understated design drew me in, and I found myself wanting to understand why it felt so refined. I’m not sure how others experience it on their first encounter, but for me, the maturity and beauty of the interface were striking.

 

And the deeper one explores, the more one realizes how much capability is hidden beneath that seeming simplicity. It’s an impressive piece of work.

 

With that in mind, let’s move on to the next part.

 

Note: All figures and observations are based on PE-bear v0.7.1.

 

 

What’s PE-bear?

Officially, PE-bear is described as “a multiplatform reversing tool for PE files. Its objective is to deliver a fast and flexible ‘first view’ for malware analysts, stable and capable of handling malformed PE files.”

 

In fact, PE-bear represents much more: strategic choices in analysis, balancing depth and efficiency, discovering threat intelligence, hunting flexible IoCs, comparing different variants, and so much more.

 

 

Exploring the Thoughtful Design of PE-bear

When I first started learning to use PE-bear and exploring what it truly offers, its visual interface immediately made everything feel intuitive and forward-moving. It’s clear that this experience reflects many years of careful development and practical refinement.

 

Many thanks to Hasherazade and contributors for sharing such valuable experience and creative ideas with the security community. Clearly, she invested considerable time and energy to make the GUI both friendly and practical. Each function isn’t isolated but interrelated and interconnected, reflecting a mature and thoughtful approach to software design. I'm truly impressed by the detailed thinking and planning that went into this, day and night.

 

From my current limited observation and personal perspective, the main features of PE-bear that drew me in include the following:

GUI Design Style

• The layout and design are calm, low-key, and easy on the eyes.

Function Highlights

• Supports loading multiple PE files and lightweight comparison of variants.
• Allows visual operation of the right sidebar with a sections map, making the GUI flexible and intuitive.
• Provides a friendly and practical string hover preview for quick inspection.
• “Disasm view” takes into account more professional analytical needs.

Workflow Integration

• Creates a seamless chain of operations: internally looping through string-scanning output and following raw data, externally finding virtual addresses, and guiding one linking directly to IDA, which shifts malware analysis from “first view” to “dive deep.”

·        The Advanced Follow features—Follow VA, Follow Raw, and Follow “Arg 0 RVA”—serve as advanced key navigation points during analysis.

Facilitates Real Understanding

• While delivering a fast and flexible “first view,” PE-bear helps analysts gain a real understanding of PE files. The more you master the file structure, the more you will master its potential.

Combining these design elements makes the “fast view” not only possible but even more powerful. In addition, the “Go to VA(hex)” feature allows seamless guiding links to external deep-dive analysis, making PE-bear an integral part of the overall workflow. It’s not about taking a PE file and immediately diving into reverse engineering; rather, malware analysis is about strategy, choice, and balance—and PE-bear reflects that philosophy perfectly.

 

 

Exploring PE-bear Through Examples
Everything comes from texts, images, and videos I shared on the X platform as follows.

n  Dump an Embedded Binary PE-bear for dumping an embedded binary. Its intuitive UI made extraction effortless. Because malware often embeds payloads with the form A in B to evade detection, pulling out the inner binary was crucial for deeper analysis and IoC hunting.

Figure 1: Dump an Embedded Binary

 

n  Rapid Strings Scanning PE-bear provides rapid string scanning and plaintext visibility inside suspicious binaries. Like DiE and Malcat Lite, it’s an effective first-step triage tool for malware such as ransomware — a quick way to spot early indicators before diving deeper into reverse engineering.

Figure 2: Strings Scanning

 

 

n  Fast Shows Structural Evolution PE-bear + DIE: Fast Shows Structural Evolution — and What It’s Changed. Compare Mode is ideal for comparing related samples in a malware family. This helps you trace the malware evolution and also study the PE structure with a GUI.

Figure 3: Showing Structural Evolution.

 

n  Visualize DLL Side-Loading PE-bear Visualizes DLL Side-Loading and Sample Correlation Practical and convenient for observing malware correlations in a single window. Also valuable for incident response and IoC collection.

Figure 4: Visualize DLL Side-Loading

 

n  PE‑Bear + DIE  Abilities vs Factory — Imphash & Rich Header This helps you group variants and attribute their build environments quickly.

     Figure 5: Imphash & Rich Header

 

n  String Hover Preview PE-bear reveals the embedded RansomNote via its string hover preview — a practical highlight that makes it perfect for quick visual triaging. PE-bear’s string hover preview is pure design insight from real analysis work.

Figure 6: String Hover Preview For RansomNote.

Figure 7: String Hover Preview For PowerShell Commands

 

n  Fast-Feedback Workflow PE-bear’s string scan + “Follow Raw” flow feels natural. That loop — scan → follow → scroll → inspect → spot → scan — keeps both panels in a single view: fast, focused, fluid. An amazing interactive, fast-feedback workflow that drives real analysis forward.

Figure 8:Fast-Feedback Workflow

 

n  Bridging PE-bear and IDA A Rapid Workflow from String Clue to Deep Static Analysis. PE-bear finds the VA — IDA chases the logic.

Figure 9:Bridging PE-bear and IDA via VA

 

n  Section Map and “Kung-Fu” Intuition In the PE-bear section map, visually compare readable strings against obfuscated ones. This quickly trains your “Kung-Fu” intuition for spotting packed vs. unpacked samples—without relying on entropy graphs. Fast mental triage helps you choose the right next step.

   Figure 10: Packed

Figure 11: Not Packed

 

n  Disasm view in PE-Bear’s Disasm view, follow “arg 0 RVA”: this refers to the RVA (Relative Virtual Address) of the first argument passed to a function. This is extremely useful for quickly spotting pointers to strings, structures, static configuration blocks, and so on.
This part is not as simple as string searching, but it takes into account more professional analytical needs.

Figure 12: Flexible and Useful Disasm View.

The examples presented above illustrate my current understanding and perspective with my limited knowledge. In fact, I'm still learning and digging, and I would like to record this real process, and other deeper features remain to be explored. I’m delighted that PE-bear—both beautiful and powerful—will become a key component of my analysis reports throughout my future malware research.

 

In short, PE-bear is an organic whole internally, while externally it seamlessly connects to deeper reverse analysis. This combination is truly remarkable and reflects innovative design.

 

 

Observation on my personal perspective

PE-bear is an example of pursuing excellence, which is reflected not only in its attention to detail but also in its grasp of the overall design, especially in its dedication to showcasing practicality and efficiency. In addition, the layout and design are calm, low-key, and easy on the eyes. At the same time, it balances the needs of analysts at different levels. All the things make it beautiful!

 

To be honest, I greatly appreciate it; most notably, the designers subtly conveyed an awareness, motivation, and real action to reduce unnecessary dependence or maximize the fast and flexible “first view” with a friendly GUI, or rather, the interpretation of doing things to the extreme.

 

Finally, on the exploration process, a thought naturally comes to mind: could it be possible to automatically generate a lightweight but effective or for-reference static analysis report or quick preview report based on this amazing Portable Executable reversing tool? More broadly, can other similar tools be envisioned to achieve the same level of integration and insight?

 

Epilogue: What This Exploration Taught Me

The spirit of technological tradition endures, yet truly appreciating it demands an eye for beauty and the patience to pause and reflect.

Figure 13: Auguste Rodin’s Quote.

 

End of Article

 

 

 

 

 

Seeker(李标明) · @clibm079    

China · Independent Malware Analyst & Researcher

Revisiting SubVirt & Blue Pill: From Attacker Proof-of-Concepts to Defensive Foundations

 

Revisiting SubVirt & Blue Pill: From Attacker Proof-of-Concepts to Defensive Foundations

How early VM-based rootkit research shaped the architecture of modern system defense

 

 

“To understand the immeasurable, the mind must be extraordinarily quiet, still.”
— Jiddu Krishnamurti

 

 

Seeker(李标明) · @clibm079    

China · Independent Malware Analyst & Researcher 

From 2025.10.22 to 2025.10.29

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Prologue: Non-VM-Based and VM-Based Rootkits

Last time, on 2025.10.14, I published a report about “Regin Static Analysis of Its Lightweight VFS Abstraction Layer” and other rootkit reports the day before, they were old classic or legacy rootkits.

 

The legacy rootkits were extremely popular; this era is considered to be the golden age of rootkits. For personal record of study, I might define the golden age as something like “Approximately 2005 to 2014 (±1 year).”

 

So I was very curious about the rootkit’s revolution and what’s happening from 2015 to 2025. I keep seeking and noted both SubVert and Blue Pill, which are modern rootkits called virtual machine-based (VM-based) rootkits. They are surprising me. So here I would like to share my study and personal view.

 

Before beginning, here let’s call the classic or legacy rootkits as non-VM-based. So it is a little bit clear and an intuitive way to categorize them for my study or personal perspective. Now, there are two types of rootkits: non-VM-based and VM-based rootkits.

 

 

Non-VM-Based Rootkit

About this type of rootkit, as we know, they operate within or on top of the OS, without using a hypervisor. Typical targets are like kernel structures, device drivers, MBR or boot sectors, which they do with techniques SSDT hooking, DKOM, file hiding, process hiding, and rootkit loaders in kernel space.

 

Yes, they run in kernel space. Classic rootkits operate in kernel space alongside the OS kernel, sharing the same privilege level and trust boundary. That co‑location is a fundamental design flaw and risk: it makes the kernel a single point of failure, enabling rootkits to fully subvert the OS, hide from in‑guest defenses, and maintain persistent control.

 

Classic or legacy rootkits, non-VM-based rootkits, mainly need deep OS and kernel knowledge; they don’t normally require microarchitecture expertise or hypervisor-level CPU internals.

 

 

VM-Based Rootkit

About this new type of rootkit, like SubVirt and Blue Pill, they operate beneath the OS, using virtualization as a stealth layer, installing a thin or mini hypervisor to control the guest OS, intercepting OS operations from “underneath.”

 

Here, let’s go back to history to have a simple summary about SubVirt and Blue Pill. First to talk about SubVirt and then Blue Pill.

 

SubVirt: Implementing malware with virtual machines

Figure 1: from the original SubVirt report.

 

This new type of malware, called a virtual-machine-based rootkit (VMBR), inserts a minimal host operating system and VMM into the boot process. SubVirt alters the boot chain and forces the original operating system to run as a guest, fully controlled from the underlying hypervisor layer.

 

 

Blue Pill idea

Figure 2: from the original BH-US-06-Rutkowska report.

 

The Blue Pill proof-of-concept demonstrated a different threat vector from SubVirt: rather than re-platforming the boot sequence, Blue Pill showed that it leverages CPU virtualization extensions to start a mini hypervisor that could be launched beneath a running OS, migrating the OS into a guest instead of modifying the boot chain. It is very powerful because it shifts trust below the kernel without obvious boot artifacts.

 

 

The Challenge of Creating a VM-Based Rootkit

However, the implementations in SubVirt and Blue Pill highlight that compromising the system at the hypervisor layer requires a high degree of sophistication and is extremely hard to achieve in practice, because they must master them very well, at least as follows:

1.      Deep CPU or microarchitecture expertise and ability handle CPU virtualization (VMX/SVM).

2.      One must implement a mini host OS and VMM.

3.      Complex memory & device virtualization.

 

Just the above knowledge and techniques to master are very difficult for most people to create that type of VM-based rootkit. In my personal view, it’s not an average APT, but a nation-state-level APT can do it. And to defenders, they also have to raise themselves to the same or higher level.

 

 

VM-Based Rootkit Ideas Finally Become Defense Policy

In 2006, they were both modern proof-of-concept hypervisor rootkits, Today, the ideas behind VM-based rootkits are no longer just theoretical. Modern systems use virtualization to protect critical code, isolate sensitive data, and monitor for malware, after all for defense. Here are just some real-world applications:

1.      Cloud Security – isolate sensitive workloads in protected mini-VMs.

2.      Application Isolation – Qubes OS.

3.      Operating System Protection – protect kernel code and credentials.

 

Yeah, today the idea and perspective are implemented as the main defense policy and trend, with deep implications for modern OS (Windows & Linux): as OS vendors and security products incorporate virtualization-based security (VBS, HVCI, and VM introspection).

 

In order to further understand what the core change inside is, I think it is important. Let’s extend to explain them simply as follows:

1.      VBS (Virtualization-Based Security): It creates a mini-OS via hypervisor. The purpose is to isolate critical Windows processes & secrets.

2.      HVCI (Hypervisor-Protected Code Integrity): It is a part of VBS and blocks unsigned drivers; the purpose is to enforce kernel code integrity.

3.      VM Introspection (VMI): It is used for stealth malware detection; the purpose is to monitor the VM from outside.

Figure 3: Modern Virtualization-Based Security Stack.

After all, VBS, HVCI, and VM introspection are different mechanisms that leverage virtualization to build a foundation for modern system security.

In other words, a classic rootkit is a big challenge to live and persist in in this type of environment.

 

 

Conclusion

The VM-based rootkit idea, like SubVirt and Blue Pill, came from a completely new structure design mindset in modern system defense, which makes defensive policy a very high-level evolution in the modern cybersecurity field; it highlights progress on the defensive side and being positive.

 

And until now, we haven’t seen publicly confirmed, widely deployed VM-based rootkits in the wild that match the scale or stealth claims of the early proof-of-concept like SubVirt or Blue Pill.

 

While VM-based rootkits are extremely rare, the attacker mindset they introduced has already materialized in the wild through UEFI firmware bootkits like LoJax (2018), ESPecter (2021), and MoonBounce (2022), The dates above represent approximate timelines, which provide similar stealth advantages by operating beneath the operating system. These look like a practical evolution as the attacker’s perspective.

 

Revisited the SubVirt and Blue Pill and the evolution. Nowadays, a new battle is taking place between attackers and defenders of modern computer systems, and they go forward with mutual promotion, truly incredible!

 

Epilogue: What the SubVirt and Blue Pill Taught Me

1.  The type of VMBRs like SubVirt and Blue Pill taught me too much to learn.

2.  The security field is an area that requires active response. Due to its inherent adversarial nature, learning and practice are continuous.

Annotation: In all the sentences I wrote and used the word “you or your or yourself” in, it talked to me or “the malware sample itself, especially in my poem I did”, not the reader. I must clarify my motivation.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

References

[1]. https[:]//www.microsoft.com/en-us/research/wp-content/uploads/2016/02/subvirt.pdf?msockid=3358b4e5e04c69682295a69be12a689f

[2]. https[:]//theinvisiblethings.blogspot.com/2006/06/introducing-blue-pill.html
[3]. https[:]//en.wikipedia.org/wiki/Blue_Pill_%28software%29

[4]. https[:]//blackhat.com/presentations/bh-usa-06/BH-US-06-Rutkowska.pdf

 

 

 

“Do or do not, there is no try.”
— Master Yoda

 

 

End of Report

 

Seeker(李标明) · @clibm079    

China · Independent Malware Analyst & Researcher