I published the following diary on isc.sans.org: “Base64 All The Things!“. Here is an interesting maldoc sample captured with my spam trap. The attached file is “PO# 36-14673.DOC†and has a score of 6 on VT. The file contains Open XML data that refers to an invoice.. [Read more]
I published the following diary on isc.sans.org: “Getting some intelligence from malspam“. Many of us are receiving a lot of malspam every day. By “malspam”, I mean spam messages that contain a malicious document. This is one of the classic infection vectors today and aggressive campaigns are started every week.
I published the following diary on isc.sans.org: “Another webshell, another backdoor!“. I’m still busy to follow how webshells are evolving… I recently found another backdoor in another webshell called “cor0.idâ€. The best place to find webshells remind pastebin.com[1]. When I’m testing a webshell, I copy it in a VM located
Just a quick blog post about an interesting sample that I found today. Usually, modern pieces of malware implement anti-debugging and anti-VM techniques. They perform some checks against the target and when a positive result is found, they silently exit… Such checks might be testing the screen resolution, the activity
I published the following diary on isc.sans.org: “AutoIT based malware back in the wild“. One week ago I wrote a diary with an analysis of a malicious RAR archive that contained an AutoIT script. The technique was not new but I was curious to see if this was a one-shot
I published the following diary on isc.sans.org: “Malicious AutoIT script delivered in a self-extracting RAR file“. Here is another sample that hit my curiosity. As usual, the infection vector was an email which delivered some HTML code in an attached file called “PO_5634_780.docx.html†(SHA1:d2158494e1b9e0bd85e56e431cbbbba465064f5a). It has a very low VT
I published the following diary on isc.sans.org: “Malicious script dropping an executable signed by Avast?“. Yesterday, I found an interesting sample that I started to analyze… It reached my spam trap attached to an email in Portuguese with the subject: “Venho por meio desta solicitar orçamento dos produtos†(“I hereby
I published the following diary on isc.sans.org: “Maldoc with auto-updated link“. Yesterday, while hunting, I found another malicious document that (ab)used a Microsoft Word feature: auto-update of links. This feature is enabled by default for any newly created document (that was the case for my Word 2016 version). If you
I published the following diary on isc.sans.org: “A VBScript with Obfuscated Base64 Data“. A few months ago, I posted a diary to explain how to search for (malicious) PE files in Base64 data. Base64 is indeed a common way to distribute binary content in an ASCII form. There are plenty
I published the following diary on isc.sans.org: “Obfuscating without XOR“. Malicious files are generated and spread over the wild Internet daily (read: “hourly”). The goal of the attackers is to use files that are: not know by signature-based solutions not easy to read for the human eye That’s why many
