Questions tagged [malware]

Malware, a portmanteau for malicious software, is software used or created by attackers to disrupt computer operation, gather sensitive information, or gain access to computer systems.

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75 views

Start vs WinMain()

I am trying to analyze a malicious DLL and when I loaded it in IDA, I can see two functions - DLLEntryPoint and DLLMain. I then proceeded to change the format by switching the characteristics bit that ...
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1answer
351 views

Difficulty in debugging with dnSpy

I have a dotnet malware sample that I'm trying to debug with dnSpy. It has string obfuscation (contains function names such as BarriersBottomed, etc.) I cleaned the sample using de4dot and renamed ...
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1answer
244 views

General unpacking of packed malware

I did a brief survey on malware unpacking and I found several theses on automated general unpacking:Eureka, PolyUnpack, omniUnpack, Malware Normalization. However, these theses are written years ago ...
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1answer
170 views

How to detect overlay data in RTF files?

How to detect overlay data in RTF files? When officemalscanner says it detected overlay data, what does that mean ? Is overlay data specific to malicious files ?
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1answer
340 views

What is Executable Compression? [closed]

I don't know whether this is the right place for this question or this question is too basic. I was reading Antivirus Hacker's Handbook, where they talked a bit about software packers, protectors, ...
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1answer
429 views

Hidden code in dissasembly

I'm testing malware that built from single EXE file and it doesn't load any other DLLs. I can see that EXE is register as COM object (I don't know how EXE can be COM object...). But when I run it and ...
2
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1answer
154 views

Is data exfiltration possible without obvious system calls? [closed]

http://resources.infosecinstitute.com/data-exfiltration-techniques/ I am teaching myself to identify exfiltration of sensitive data with malicious binaries. One thing I have noticed, is in most ...
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2answers
708 views

Packed PE file and weird Header

I'm new to reverse engineering, so I don't know if my question will be easy or not. Right now I have an exe file, but it seems packed. In the hex Dump I do have the followings : 000003d0: 0055 5058 ...
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1answer
675 views

SWF flash analysis

An SWF file was recently detected by Windows Defender as SWF/Meadgive. I uploaded a sample to VT and only Microsoft flagged it as malicious. As of today's signatures I am not seeing any further ...
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1answer
913 views

Dump a child process created by malware with an ALTERNATIVE process hollowing process

I'm reversing a malware which uses a variant of Process Hollowing to create a process which I can't dump. I don't know what I'm doing wrong. I always see the suggestion to stop at GetContextThread , ...
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1answer
193 views

Documentation of malware reverse engineering

I'm interesting in reversing malware. The problem is, that if you analyse malware on your own you don't know how efficient you are, and with which techniques/tools/methods you can use for better ...
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2answers
90 views

Malware Samples that defeats emulators by using uncommon API calls

I am looking for a few malware samples that detects sandboxes using uncommon API calls. I understand that one of the drawbacks of OS emulated sandboxes is that the malware can use uncommon API calls ...
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1answer
112 views

Unable to properly analyze a very simple C-compiled program

I'm a RE beginner and I decided to start writing my own simple code for practice. I wrote a simple code which uses a winAPI function called CreateProcess to start a calc.exe, I've wrote it in C and ...
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0answers
56 views

Determine what architecture a piece of shellcode targets

After some personal research I didn't find any possible way or a paper to explain how to determine what architecture a given piece of shellcode may targets. The only obvious way I found would be to ...
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0answers
862 views

Unable to unpack heavly obfuscated malware

I'm trying to unpack malware packed with ConfuserEx 1.0.0 and I can't seem to get it to work. Each time I remove the anti-tamper the whole file gets corrupted. I tried all possible tools that I found ...
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0answers
585 views

What conditions can create the “Not a Valid Win32 Application” error message upon load?

I'm doing research on the PE format/Windows Loader and I am unable to locate specifics as to what creates the error "Not a valid Win32 Application" followed by a failure to load. I've tried changing ...
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0answers
129 views

Does anybody knows a good dataset for malware families? [duplicate]

Does anybody knows a good dataset for malware families? What i need is a dataset where malware are already classified in families. And is not duplicate of "Where can I, as an individual, get malware ...
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0answers
168 views

Collecting malware samples [duplicate]

Could you please list some sites from where I could download viruses/worms/trojans in .exe format. I have read the answers to the other similar questions but couldn't make much use of them. I am a ...
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0answers
203 views

Malware analysis - AntiDebugging - Malware slows down the PC while being debugged

As part of my work, I'm debugging a malware found and his behavior is pretty basic after execution: Being executed Decrypt a lot of data from memory and obtain a new PE (from memory) Create a child ...
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0answers
175 views

Malware terminated in Ollydbg after a while - Why? [closed]

I try to analyze a backdoor program with ollydbg. When I go through the assembly code by clicking the "Step Over"-Button, i stop sometimes to make a notice on a paper. Later when i want to go trough ...
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0answers
199 views

How to add xrefs to indirect call targets in IDA? [duplicate]

I was analyzing win32.ramnit's dropper for fun. Almost all the calls it uses are indirect calls. I have figured out the destination addresses using manual analysis. But how can I add this information ...
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0answers
81 views

Opinions and suggestions regarding malware sandboxes [closed]

I'm relatively new in the field of automatic malware analysis and I'd like to ask about hands-on opinions about sandboxes in the following aspects: extensibility of the product - adding your own ...
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0answers
417 views

MITRE MAEC (Malware Attribute Enumeration and Characterization) opinions and usage [closed]

I was looking at some MITRE projects and was wondering what you thought about, and if anyone was using or contributing to, the MITRE Malware Attribute Enumeration and Characterization project: https://...
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3answers
968 views

Best and smarter way to improve unpacking skills

I want to find a way to improve my unpacking skills, i am not a noob but i miss steps from simple to hard packers. I saw lot of video tutorials, the most of the time i see "click F9 x times to reach ...
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3answers
283 views

What is the average time for “defusing” malware self-protection mechanisms?

I always wondered how much time is needed to get rid of all that anti-VM/crypto/protector/anti-debug stuff (without analyzing actual payload and purpose), especially if you're dealing with malware on ...
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2answers
1k views

Anti-VM and anti-sandbox malware samples

I'm learning malware analysis. I'm looking for malware samples that terminate themselves when recognize working on a VM or sandbox. Thanks.
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3answers
2k views

How can I export only the opcodes from objdump (or any other program)

I have multiple malware files, I want to do an analysis with the opcodes. Im able to export everything to text but I only need the middle column. Any idea on how can I solve this? In other words of ...
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3answers
238 views

Cyber security student wanting to start learning reverse engineering [duplicate]

I'm really interested in learning reverse engineering. Especially in regards to malware. Any help is much appreciated What should I learn before I start to learn reverse engineering? Is learning C/...
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2answers
99 views

Test malware files in host machine?

To analyze malware files we are using virtual machine and virtual box but some of malware detect the environment and will not do its work properly. I want to know how to test malware files with out ...
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1answer
131 views

What are the overall features used in static analysis of malware? Is file property among the features used in static analysis of malware?

I was looking at the paper: "Improved Detection for Advanced Polymorphic Malware" by James Fraley who claimed to have used static, dynamic and file properties for increased malware detection. But is ...
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3answers
303 views

What is the average time for malware analysis?

I was wondering what is the average time for you to classify (by reverse engineering) if a suspicious file is a malware or not? Thanks
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2answers
595 views

Debugging Win32.Upatre - why does Ollydbg fail to analyze this?

So I've been looking at this thread - Where can I, as an individual, get malware samples to analyze? And grabbed myself a binary sample of Win32.Upatre from Halvar Flake's blog. I started analyzing ...
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1answer
653 views

How to change PE signature? [closed]

I'm looking for a way to recognize an executable file as a NullSoft installer. I´m trying to prove that a malicious software is capable of changing the PE signature so we can not trust in some tool ...
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3answers
2k views

Malicious word document shellcode extraction

I am playing with some malicious MS Word documents which exploit a vulnerability in Word 2k3/2k7 to launch the shellcode. I am able to run it dynamically and get the drop-bys. However, I am interested ...
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2answers
146 views

Emotet invoice, what is the embedded file inside the word document

This pastebin hosts current URLs hosting the fake invoice of Emotet malware, which is the dropper part of the malware. The document is a Office Open XML, and there are two large non textual segments ...
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1answer
2k views

Unable to dump malware assembly using objdump

I'm trying to dump assembly code of a ShellShock malware explained in this blog post: MMD-0027-2014 - Linux ELF bash 0day (shellshock): The fun has only just begun... . After dumping using objdump -...
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1answer
619 views

Are jump instructions targeting addresses in ntdll a sign of malware?

For fun I downloaded an installer from a "driver downloads" website. I do NOT intend on installing it, but I was interested to check it out just to see what it looked like. I tossed it into Ollydbg (...
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1answer
2k views

How to dump a DLL not listed using Process Explore and similar tools

I am trying to reverse engineer a DLL that may contain malware. One thing I noticed is that it hides itself from the DLL LDR_MODULE list. So, when I use Ollydbg or smiler tools I do not see it and ...
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1answer
736 views

How to convert Unexplored data in IDA Pro to code?

I am analyzing a malware, it has a lot of confusing methods, I wrote an idc script to remove confusion, use the MakeCode() function to convert some Unexplored data into code, but there are still some ...
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1answer
401 views

bypassing anti-VM inside protected samples

This is a good starting point. As you know: Sandboxes and virtual environments (hypervisors) are full of artifacts that betray their analysis environment. Malware can protect itself against these by ...
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1answer
2k views

How to analyze a child process created by malware by process hollowing mechanism using immunity debugger?

When I analyzed this malware sample it was invoking api's related to creating additional processes. With the process explorer I saw the debugged process is creating a new process. Please suggest any ...
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1answer
124 views

Is this request mask algorithm reversible?

I am trying to understand an algorithm from a malware I found. This algorithm encodes http request to C&C. The decompiled version is taken from IDA. There are some comments I wrote. The problem ...
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2answers
175 views

Obfuscation by changing the order of a malware behaviour

I know that there are some obfuscation techniques which can lead to slowing or even failing the detection of malware when static analysis is used. However, is there a similar technique that changes ...
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1answer
189 views

De-obfuscation - Emulation-oriented vs Script-oriented

What are the advantages of each method when employing de-obsfucation of potentially malicious code? I've been told to always use emulators like x86emu since it doesn't actually run the code when ...
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1answer
123 views

Rootkit.Fileless.MTGen Reverse Engineering

Has anyone tried seeing what's inside of this malware? It ended up on one of our work machines. I copied the files to a thumb drive before setting the machine up for reimaging. Though the AV software ...
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1answer
157 views

Which RE tool is missing?

I am analyzing a malware at the moment which scans for a lot of filenames and ClassNames to recognize if it is under supervision or not. My problem is, that all the filenames and ClassNames are ...
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1answer
145 views

Likely malicous Javascript-interested in how it works

Got this interesting bit of code compressed in an email named "Install-MSOffice365-WebView-Plugin-Update-0.165.11a.exe.js" that is undoubtedly malicous, but was curious what it does and am not much of ...
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1answer
117 views

IDA pro can not resolved section after unpacking procedure

I had a sample which was packed by a packer and I unpacked it using OllyDbg but after unpacking still IDA can not resolve the section and show most of instructions as DD. Is this sample still packed ...
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1answer
285 views

Question about process injection

During an analysis, I found the following piece of malware: ... lea eax, [ebp+ThreadId] push eax ;lpThreadId push ebx ;dwCreationFlags push [ebp+...
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1answer
284 views

Tracing adware on windows - ads showing up in browser

Sometime ago I came across this situation: Windows 7 machine infected with adware, ads tabs opening up in chrome out of nowhere. Pretty invasive stuff. In the end i got rid of it with some malware ...