Tag Archives: malware

How to Write Simple but Sound Yara Rules – Part 3

It has been a while since I wrote „How to Write Simple but Sound Yara Rules – Part 2„. Since then I changed my rule creation method to generate more versatile rules that can also be used for in-memory detection. Furthermore new features were added to yarGen and yarAnalyzer. Binarly The most important feature of […]

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System Files Typical File Size Detection with YARA

YARA Rules to Detect Uncommon System File Sizes

YARA is an awesome tool especially for incident responders and forensic investigators. In my scanners I use YARA for anomaly detection on files. I already created some articles on „Detecting System File Anomalies with YARA“ which focus on the expected contents of system files but today I would like to focus on the size of […]

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Yara Signatures

How to Write Simple but Sound Yara Rules – Part 2

Months ago I wrote a blog article on „How to write simple but sound Yara rules„. Since then the mentioned techniques and tools have improved. I’d like to give you a brief update on certain Yara features that I frequently use and tools that I use to generate and test my rules. (mehr …)

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DLL in Sandbox

Smart DLL execution for Malware Analysis in Sandbox Systems

While analysing several suspicious DLL files I noticed that some of these files (which were obviously malicious) didn’t perform their malicious activity unless a certain function was triggered. The malware used a registry entry to execute a certain function that is exported by the DLL called „InstallM“. I had to run „rundll32.exe malware.dll,InstallM“ to trigger […]

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Telekom Rechnung Januar

Malware Welle – Januar 2014

Derzeit rollt eine interessante Mail-Welle durch Deutschland und adressiert vor allem deutsche Unternehmen. Es handelt sich wie üblich um eine Rechnung von „Telekom/Vodafon/Volksbank“, die als Link in der Mail hinterlegt ist. Der Link verweist nicht auf eine EXE oder ZIP sondern auf ein directory. Zurückgeliefert wird beim Aufruf aber ein ZIP File. Im ZIP befindet sich eine […]

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