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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4answers
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Unpacking and dumping using ollydump

I am trying to learn how to unpack a malware. I am trying this with ollydbg. However, when I try to dump the unpacked using ollydump plugin. It prompts the error "Bad DOS signature!!". Could someone ...
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2answers
2k views

Recognize the library functions of statically linked executable file in IDA Pro

Recently I worked on a Linux program which has all of its symbols stripped. Opening it with IDA resulted in none of its functions identified. Thus I tried to extract any usable information from the ...
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1answer
139 views

I'm would like to view this malicious payload, but am having trouble decoding it

This is a gzip compressed base64 string. I tried decoding it with an online converter but it said the data was corrupt. Can anyone decode this? H4sIAAAAAAAAAL1X6W6jyBb+...
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1answer
683 views

Resolve Addresses To Function Names

I have a malware sample that wraps LoadLibrary & GetProcAddress duo to dynamically resolve functions. After this wrapper is called the value stored in eax(which is the function name)immediately ...
5
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2answers
832 views

Reversing Self-Modifying Malware

recently i got my hands on one sample that self-modifies its .text section. So, I placed a breakpoint on .text section on write operation and then continued. I found out that it zeroes out the .text ...
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1answer
139 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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0answers
1k views

Attaching to Dalvik static function using Frida in order to disable emulator detection

I have a re-occuring issue with Frida (I'm using Frida and Frida-Server for Android x86_64 ver.: 10.6.11), where I try to hook a function and override its functionality, but for some reason I get ...
2
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2answers
906 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
2k views

How can I dynamically debug a malicious DLL? [duplicate]

English isn't my first language, So I will do my best ) I am trying to analyze some malware NotPetya and I can run the malware by running : rundll32.exe notpetya.dll #1 I am using Olly and trying ...
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1answer
279 views

Getting Xrefs to Windows Library Functions in IDA Pro

Ok so let's say that a program obfuscated its IAT and i can't see it in IDA Pro. In OllyDbg there is a plugin where you press Ctrl+G you can search for a library function and set a breakpoint even ...
6
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1answer
3k views

How tools like PEiD find out the compiler and its version.

How tools like PEiD and CFF explorer find out the compiler and its version. I am analyzing a executable file. Which shows: Borland Delphi 3.0 But the section names .text .rsrc. Which is usually ...
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2answers
556 views

Manual unpacking petya ransom [closed]

I want to manually unpack red Petya ransomware. I used Ollydbg for unpacking and set breakpoint on VirtualAlloc to see the "MZ" header in memory dump, and saved it to a file. But the saved file is not ...
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1answer
124 views

Information about packers

i was trying to search for some information about packers just to learn more about it, there is a lot of stuff out there but its hard to find something that really explain that good and clear, I would ...
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0answers
272 views

What do malicious programs use the ESENT registry key for?

I was analyzing a piece of malware and noticed it created this registry key. hkey_local_machine\software\microsoft\ esent\process{malware file name}\debug Some googling told me that esent is just a ...
2
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0answers
712 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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1answer
1k views

Extracting embedded dlls from .NET executable

I have a .NET executable that apparently has some embedded DLLs. It's just one standalone executable. I opened this executable with JetBrains dotPeek and ILSPY, both decomiplier are showing DLL names ...
3
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1answer
443 views

How can I determine if a piece of code is an encryption algorithm?

I am trying to reverse engineer a malware, and came across a piece of code that I suspect is an encryption/decryption procedure, however I do not know for sure. I can recognize that it extracts its ...
2
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2answers
196 views

VBA code detection in MS office documents

So, lately I've been working on a project involving malware which gets spread via MS Office documents and, among other things, I need to detect the VBA code in appropriate document streams. I've read ...
4
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2answers
698 views

What PE anomalies can crash the Windows Loader or cause a file to not load?

I do malware analysis on Windows. I run hundreds of Windows PEs per day and it is actually relatively common for a file to not run (or sometimes not run on just one specific version of Windows) and I ...
1
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1answer
156 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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0answers
71 views

Where can I get a good description about windows build-in exe programs like wupdmgr.exe?

I was checking the Strings for Lab01-04.exe from Practical Malware Analysis and I found wupdmgr.exe and I face this every time I search for an exe. Is there any "msdn" alike repository but for exe ...
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1answer
772 views

Aside from Assembly, should I learn C or C++?

With Malware/Virus analysis being heavily dependant on one's ability to read the the Assembly Code generated by the Disassembler... being familiar with the Assembly Language is naturally the most ...
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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
3k views

Detecting packed 64-bit Windows Portable Executable (EXE) files

What programs are the most useful to detect if a 64-bit PE file has been packed (main focus is on EXE files). I am not interested in the packer used I would just like to know if the file is packed or ...
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1answer
127 views

What is the relation between binary (executable) instructions and execution instruction [closed]

What I want to know is that is there any similarity or may be difference between a binary instructions and an execution instruction of a binary ? In other world, in area of malware analysis a binary ...
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0answers
117 views

What is the name of this technique?

A while back, on a Linux system, I found a strange binary being executed at seemingly random times with some strange arguments, briefly appearing in ps. There was nothing to be found at the usual ...
2
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1answer
440 views

DGA(Domain Generation Algorithm) based malware files

Where i can get DGA (Domain Generation Algorithm) based malware files for analysis? And,Can I get malware family names which is using Domain Generation Algorithm?
2
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1answer
1k views

how to overcome setunhandledexceptionfilter in ollyDebugger?

I am debugging a malware sample which is using setunhandledexceptionfilter() for anti-debugging. I don't know how to handle this. Can you guys please explain the setunhandledexceptionfilter() anti-...
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1answer
92 views

Need help in understanding the code of a “Malicious” file [closed]

I'm testing a malware sample : hxxps://www.virustotal.com/en/file/55f4cc0f9258efc270aa5e6a3b7acde29962fe64b40c2eb36ef08a7a1369a5bd/analysis/ This is a malicious executable file. When executed in ...
5
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2answers
551 views

Safe way to download a malware payload?

I'm trying to analyze a piece of malware that is most-likely a downloader. During dynamic analysis on an isolated VM network, Wireshark registered a GET request to a server for what I believe is the ...
3
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2answers
2k views

How to debug malware that injects itself into another process?

I am kind of new in the field of reverse engineering, so sorry if it is a silly question. I have to analyse some malwares for my bachelor thesis and I am currently trying to reverse engineer a ...
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2answers
657 views

sandbox for analyzing network traffic

I am in search of looking an open source sandbox that has the following features: - route my network traffic to the sandbox for analysis - perform analysis on network traffic to detect malicious ...
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1answer
122 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 ...
0
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1answer
84 views

Where can I get systematic problems and solutions for debugging?

I know PEFile headers, assembly language, and other basic stuff. I am looking for some site or book which systematically teaches me debugging and reversing. Something like "Let us C" for C language. ...
0
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1answer
917 views

Can't debug a service

I am working on Lab11-03 in "Practical Malware Analysis" book. The malware I am analyzing trojanized the file cisvc.exe which is the indexing service in Windows XP. After that the malware ...
7
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2answers
2k views

Virus uses a custom XOR encryption and need help possibly cracking it / Reversing EXE

As stated in my previous question i was infected by a encrypting virus that encrypts two 1024 byte blocks of any given file (First 1024, and last 1024) in some type of custom CFB XOR encryption. I ...
2
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1answer
434 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, ...
11
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1answer
790 views

Randomly picking up a x86 register for an instruction

I came around a piece of malware which i am analyzing and have found that it uses some kind of math to randomly selecting a register for a specific instruction Which i don't understand how this ...
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0answers
56 views

Reverse Engineer an iOS MP4 Bug [duplicate]

Recently I came across and malformed mp4 that when played on the iPhone would crash the device. I am trying to figure out which bits are specifically responsible for the crash. I am wondering if ...
1
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1answer
3k 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 ...
0
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1answer
703 views

Restoring an Infected appending virus EXE file by

I'm trying to restore a file that was infected by a virus (gaelicum or tenga) It's an appending virus. This is the warning I get when opening it in OllyDbg : --------------------------- Entry Point ...
1
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1answer
127 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
487 views

How to download Linksys firmware from router

A co-worker gave me his mom's Linksys router that he is convinced has been hacked to include a MitM. We could just upgrade the firmware, but that wouldn't be any fun and so I thought this might be a ...
4
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1answer
200 views

Where can I, as an individual, find clean programs to analyze?

This question includes a good list of sources where an individual might collect malware samples for analysis. I'd like to get a large number of public, non-malicious programs for the purpose of ...
0
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1answer
143 views

Unknown algorithm in forloop

i am reversing a malware sample .but getting stucked in a loop below.the line written in the bold letter generated random letter like "/2","/lm32" etc to EDX.The thing is that ECX does not contains ...
2
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1answer
363 views

Why is otkloadr.WRAssembly.1 reference present in a office file?

I was working with a RTF file and I found the string "otkloadr.WRAssembly.1" present inside the file in plain sight. I know that many exploits use this for loading the msvcr71.dll (non-ASLR module). ...
2
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2answers
1k views

Unable To break TLS callback function using ollydbg

while trying to debug a binary which have TLS callback functionality,i am not getting any result.i have put "System entry breakpoint" as in ollydbg Event option.Binary breaks as system breakpoint ...
2
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1answer
995 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
577 views

Malware samples to analyze with existing disassembly?

Hopefully this question isn't get marked as Duplicate, since it differs from the following question: Where can I, as an individual, get malware samples to analyze? I'm looking for samples (ideally ...
2
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1answer
238 views

Distribution of malware obfuscation types

There are several statistics and numbers out there of current malware families and their distributions. However, I'am looking for statistics which shows the distribution of malware differed by their ...