SANS Internet Storm Center - Cooperative Cyber Security Monitor
Updated: 36 weeks 3 days ago
Smartphones today carry an unbelievable amount of sensitive information. As absolutely everything is going mobile these days, we have to pay special attention on security of mobile applications, specifically data at rest (data stored on a mobile device) and data in transit (data transferred to the target server).
Last weekend, I caught on VirusTotal a trojan disguised as Windows IRC bot. It was detected thanks to my ‘psexec’ hunting rule which looks definitively an interesting keyword (see my previous diary). I detected the first occurrence on 2018-03-24 15:48:00 UTC. The file was submitted for the first time from the US. The strange fact is that the initial file has already a goods code on VT (55/67) and is detected by most of the classic antivirus tools.
Over the past two weeks, I have noticed several attempts against my honeypot looking to exploit CVE-2017-5638 Apache Struts2 vulnerability that look very similar to this python script. Today alone I recorded 57 attempts against port 80, 8080 and 443. T format of the queries I have observed over the past two weeks contain one of these two requests:
"Error 19874: You must have Office Professional Edition to read this content, please upgrade your licence.", (Sat, Mar 24th)
I was sent a document that could (supposedly) only be read with Office Professional. Of course, this was a malicious document (MD5 151a561d41eb3e960676b293e726d8f3) with macros.
Today's diary is an extension to the one I posted yesterday about hunting for malicious files crossing your network. Searching for new IOCs is nice but there are risks of missing important pieces of information! Indeed, the first recipe could miss some malicious files in the following scenarios:
If classic security controls remain mandatory (antivirus, IDS, etc), it is always useful to increase your capacity to detect suspicious activities occurring in your networks.
What’s happening with blackmails? For those who don't know the word, it is a piece of mail sent to a victim to ask money in return for not revealing compromising information about him/her. For a few days, we noticed a peak of such malicious emails. One of our readers reported one during the weekend, Johannes Ullrich received also one. A campaign targeted people in The Netherlands.
Just a quick reminder about some bad practices while handling Windows Administrator credentials. I'm constantly changing my hunting filters on VT. A few days ago, I started to search for files/scripts that use the Microsoft SysInternals tool psexec. For system administrators, this a great tool to execute programs on remote systems but it is also used by attackers to pivot internally. This morning, my filter returned an interesting file with a VT score of 11/66. The file is a compiled AutoIT script. This kind of malicious files is coming back via regular waves. AutoIT executable can be easily decompiled. To achieve this, I'm using Exe2Aut.exe. This tool has not been updated for a while but is still doing a good job.
Wireshark can capture USB traffic, provided you fulfil the necessary requirements.
Wireshark-announce: [Wireshark-announce] Wireshark 2.5.1 is now available
VMware has released the following new security advisory:
This is a guest diary by Joshua Barton