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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106 views

unpack a malware manually [duplicate]

I`m working on this malware to analyze: http://www.freeuploadsite.com/do.php?id=74209 password: infected It seems it is packed but when I use "PE View" , etc tools to find the packer, their results ...
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2answers
2k views

Need advice : Reverse engineering a pdf with shellcode

Problem : I try to find the plaintext which was hidden at pdf inbuilt with shellcode What i tried : I received a pdf which contains javascript with it ,i dig the pdf as follows : Exploring ...
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2answers
576 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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0answers
98 views

How do I become a Malware Analyst? [duplicate]

Sorry if this is posted in the wrong section. A little about me: I'm going to be a sophomore in the fall at university, my major is Computer Science (Information Assurance). I've been interested in ...
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1answer
295 views

What are the risks of running a decompiler? [closed]

I have a binary file which is potentially a virus and I wish to look into its internals. I need to be cautious as I don't want it to run on my system. That's why I ruled out gdb. I've searched and ...
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1answer
708 views

Studying Zeus 2.X

I'm doing some study on Zeus 2.x, trying to wrap my head around how it works. By using this code. I've built my own builder to work on my test environment. Right know I want to do a very specific ...
2
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1answer
528 views

Why does an exe's import Table have two refrences to kernel32.dll (or any other dll)?

According to what I know, Import Descriptor table is made of an array of _IMAGE_IMPORT_DESCRIPTOR structures. There is one _IMAGE_IMPORT_DESCRIPTOR for every dll that is imported. I have an exe which ...
13
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4answers
4k views

INT 2D Anti-Forensic Method

Inclusion of an INT 2D instruction appears to be a fairly common anti-debugging tactic used by Windows malware authors. From what I understand, it causes a process to act differently when a debugger ...
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3answers
932 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 ...
3
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2answers
8k views

When to use Windbg and Ollydbg?

According to what I know :WinDbg uses debugging information (pdb/symbol files) for debugging.So ,for example say I get a unknown exe (malicious) can I debug it since I'll not be having its .pdb. Is ...
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0answers
210 views

Analysis target modifies debugging registers during initial file open in ollydbg

While opening a binary in Ollydbg, I get a warning that the debugged program has modified the debugging registers. The following entry is in the log: Address: 7749218E Modified debug registers of main ...
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1answer
1k views

Prevent malware from deleting itself during installation on Windows x64

Can anyone suggest a tool to prevent a malware from deleting itself on Windows x64? The purpose is to collect all the components of the whole process of infection. I've looked at CaptureBat, but its ...
3
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2answers
377 views

Will this code run in real machine or is it some kind of Anti Reversing code?

I am reversing a file which is not running properly in Vmware.The code from the AEP is as shown below : POP EDI ; value of edi is 0x7C816D4F kernel32.7C816D4F PUSH EAX ;value of eax is 0 INC ...
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0answers
438 views

Does malware ever purposely embed resources to thwart resource analysis and extraction

I have been analyzing a Kazy (derp) Ramdo variant that is relatively recent and was surprised to see an access violation in resource hacker when trying to view an embedded bitmap. Is this common or ...
3
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1answer
841 views

Where to find a full analysis of the encryption scheme of CTB-Locker?

CTB-Locker is a currently active ransomware that encrypts files to lock users out. Here are a few links about this malware: A new generation of ransomware: Elliptic curve cryptography + Tor + ...
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2answers
1k views

Unpacking a backdoor program for studying

I wanted to learn something about unpacking malware manuelly and found the following link: writequit.org/blog/?p=165. As you can see, the malware in that example begins with the PUSHAD instruction....
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1answer
314 views

Where can i download malware variants [duplicate]

How/Where can i get variants of a malware ? The only thing that concerns is that the variants must be a continuous update of the previous one
4
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1answer
889 views

What is the benefit or reason of using a static disassembler over a dynamic disassembler in terms of malware analysis?

I know that Dynamic program analysis is the analysis of computer software that is performed by executing programs on a real or virtual processor. while Static program analysis is the ...
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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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4answers
433 views

Search remote malware zoo for homologous samples

I've got the following problem: I'd like to find new binaries of a certain malware family -- unpacked -- for subsequent analysis (active C&C comms analysis). Is there a database of binaries ...
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1answer
274 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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2answers
692 views

Decompiling .NET marshaled code

There's a .NET malware sample I'm trying to analyze, which goes more or less like this: internal static class Class1 { public static byte[] Code = new byte[] { 9, 249, ...
1
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1answer
283 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 ...
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1answer
497 views

Computer Malware: More complex than metamorphic?

I have read the topic on oligo-, poly- and metamorphic malware. I have done a quick google search, and it seems like the concept of metamorphic malware was already known in the DOS age and in the ...
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0answers
258 views

Is there any technique called “DLL Replacement”?

I know a techinique is called: Process Replacement , I have searched but could not find any article about "DLL Replacement", in which malicious programs can replace a legal DLL (eg. a third party DLL) ...
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2answers
3k views

Anti-debug techniques for MS-Windows?

Is there any anti-debugger tricks used by malware other than interrupt INT 0x2D ? And, how do they work ? Working examples would be really nice !
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1answer
961 views

How does this test for debugger [closed]

While reading a book it mentioned that the following code is usually used to as an antidebugger mov eax, large fs:18h mov eax, [eax+30h] movzx eax, byte ptr [eax+2] retn I don't ...
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3answers
4k views

How to figure out which imported function(s) in a virus determine its behaviour?

I want to know how to find the functions which is interesting in malware tools. For example, I have a sample of unknown virus (this sample is lab01-01.exe in the book practical malware analysis lab1-...
2
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1answer
153 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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1answer
617 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
10k views

Which IDA Pro Signature should be used for Borland Delphi 6.0-7.0 binaries as reported in PEiD?

I am currently reverse engineering a binary written in Borland Delphi 6.0-7.0 as reported by PEiD. Is there a recommended signature to use when looking at this binary in IDA Pro? I currently am using ...
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1answer
128 views

How to decide file is malware or not? [closed]

How should I decide file is malware or not. Before reverse engineering any file, I should be suspect the file. What are the various ways to decide if exe is malicious? Thanks
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1answer
2k views

How to create a virus signature from decompiled source

I have a problem where I have to create a virus signature for the Stoned Virus (Although this could apply to any virus/file). Let's assume I have a copy of the compiled and decompiled program. I then ...
2
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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 ...
4
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3answers
2k views

How to break on not-yet-loaded kernel driver

I've been reversing a sample of the Uroborus trojan for my own learning joy. I'm having a hard time following it once it loads a windows kernel driver that implements the rootkit. I've set up my ...
6
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2answers
592 views

Reverse engineering Perl-compatible regular-expressions

I'm dealing with a piece of malware that does extensive use of PCRE (Perl-compatible regular expressions). Normally I would be able to read them, but it seems they're in some kind of binary format (...
1
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1answer
600 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 (...
5
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2answers
275 views

How can we determine that malware are related?

I am curious to know about how researchers can know when different malware are related. for example: Stuxnet, Flame or Duqu, are told to be written by the same group. Does anyone know how they figure ...
5
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2answers
3k views

how to reverse DeviceIoControl?

I have started reversing this piece of malware. At some point it creates a service and starts it, then immediately it calls the function DeviceIoControl and the malware went from "paused" to "running" ...
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1answer
770 views

How do anti-virus programs catch a virus? How they detect it? [closed]

I need to know how anti-virus programs catch malware. Do they do it with hash numbers or not?
3
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1answer
424 views

Trouble analyzing a ransomware

I got this fake-av sample , and I want to reverse it . But the problem is that it exits after few commands . Here are the steps : When loaded in Ollydbg it pauses at: 00401000 > $ 8D9404 7713210&...
14
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3answers
2k views

How do AV vendors create signatures for polymorphic viruses?

I was working on a hobby AV project using ClamAV's engine. While ClamAV is a good open source engine, it has poor support for detecting polymorphic viruses. The latest updated version failed to detect ...
6
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4answers
684 views

How antiviruses name malwares

While analyzing a binary online through the virustotal service , I found out that different AVs named the binaries differently.For instance, for that same binary Norman named it Obfuscated_A, ...
4
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3answers
281 views

Tool for checking if there is any patch in the loaded module

I'm looking for a tool that is able to check loaded module for any placed patches even on not exported functions. I'm aware of Gmer, RKU and Co. and frankly I don't really trust their results.
1
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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 ...
5
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2answers
5k views

How to unpack files packed with multiple packers?

As I am just getting started in RE, I've mostly faced files packed with a single-layer of packing , such as UPX, ASPack, etc. Unpacking these protections is fully documented online. The problem ...
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4answers
1k views

Does learning Metasploit help me in reverse engineering and malware analysis?

I learned basis of assembly language with, both, AT&T and Intel style. After that I gone through buffer overflow and how to use shellcode with it. Should I go for Metasploit now?
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2answers
8k views

What are the different types of packers?

I know the basic principle of a packer. Basically, it is a small routine launched at the beginning of the program that decompress the actual program and jump to it once achieved. Yet, it seems that ...
3
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1answer
148 views

IDA debugging API's security

I recently saw funcap, a plugin that captures function calls made by a binary using IDA's debugging API. I have setup IDA on my host machine. My VMs aren't fast enough to run IDA in them. How do you ...
5
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3answers
3k views

Is learning assembly enough to become a malware analyst? [closed]

I am a C/C++ developer and I have started learning assembly language programming with the goal to become a malware analyst. I know it is not enough to just know how to read assembly to become a ...