Search Results for: yara

Templates with bad intentions

A few days ago while analyzing several emails I came across one that contained a suspicious attachment. It was a .docx document that at first glance had nothing inside but it occupied 10 kb.

The mail had passed all the barriers, both SPF, as the two antiviruses that gateways have, and also the anti-spam filter.

The .docx file can be treated as a tablet. Once extracted its content, I began to analyze all the files in the directory in search of domains or IP addresses that could be seen clearly:

And I managed to find something interesting inside the path word/_rels/document.xml.rels where the following appears:
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Analysis of Linux.Helios

For several weeks we have been detecting a new variant of malware for Linux and IoT architectures from the malware laboratory of S2 Grupo, registered for the first time on the VirusTotal platform on October 18, which we have called Linux.Helios, due to the name of certain functions present in the sample.

We emphasize that the main antivirus signatures do not unanimously classify this sample: they range from ELF.DDoS to Tsunami, through Gafgyt or Mirai.
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Taking apart office automation documents with OfficeMalScanner

One of the main routes of malware infection is through office automation documents. They represent a very potent vector of infection, specially in directed attacks and phishing campaigns.

These documents are crafted to carry hidden macros, OLE objects, executables, etc., which, once the user opens the document, conduct a series of malicious actions to obtain information with the idea of profiting from it or simply damaging the system. Generally, this type of generic malware downloads other malware for the Internet (droppers), exploits system vulnerabilities, duplicates itself to assure its lifespan in the system, exfilters user information, etc.

A very useful tool for analyzing and detecting anomalous patterns in office automation documents is the “OfficeMalScanner” suite, which you can download from the author’s web, http://www.reconstructer.org/.

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