Last Updated: 2018-11-29 02:45:05 UTC
by Brad Duncan (Version: 1)
Shade ransomware was spotted in the wild as early as 2014, and it was first called Troldesh. I previously wrote an ISC diary on malicious spam (malspam) pushing Troldesh ransomware two years ago in November 2016, and I also documented a later example in March 2017.
However, Shade/Troldesh ransomware has been spotted in the wild since then. I searched Twitter and found a handful of sightings in the past few weeks. Today's diary reviews recent examples from a campaign using Russian-language malspam to push Shade/Troldesh, and it also examines an infection from Wednesday 2018-11-28.
Recent campaign since October 2018
This investigation started after I ran across a Russian language email with an attachment that caused a Shade/Troldesh ransomware infection after I checked it in my lab environment. I hadn't paid much attention to this ransomware family in a while, so I decided to look into it.
My first step in the investigation was checking URLhaus. There I found approximately 50 URLs reported as an executable and tagged either Shade or Troldesh (or both) since October 2018. Many of these URLs ended with sserv.jpg, and a search on that revealed 71 URLs reported since 2018-11-01. I added more URLs after my investigation. Not all of these URLs reported to URLhaus were tagged Shade or Troldesh, but they fit the same general pattern that I'd seen from my infection traffic.
Searching through VirusTotal Intelligence, I found Russian language malspam with attached zip archives pushing Shade/Troldesh ransomware since at least 2018-10-30. I collected 12 examples to investigate for this diary.
The emails are in Russian, and they claim an order or a request from a bank.
An infected Windows host
Almost immediately after the initial Shade/Troldesh malware binary is retrieved, the infected host generated Tor traffic. Then the infected host checked it's IP address and generated encrypted SMTP traffic to smtp.mail.ru.
After four cycles of IP address checks and SMTP traffic, the infected Windows host generated a great deal of web traffic. This reminded me of click-fraud traffic.
The following are indicators from this malspam campaign and the associated infections:
- Examples found dated as early as 2018-10-30
- Various spoofed sending email addresses
Attachment names noted so far:
Some SHA256 hashes for attached zip archives:
Some SHA256 hashes for extracted JS files:
URLs generated by the above extracted JS files:
SHA256 hashes of Shade/Troldesh ransomware retrieved from any of the above URLs on still active on 2018-11-28:
Malware from an infected Windows host:
- File size: 2,645 bytes
- File name: Okritie.zakaz.docx.zip
- File description: Attached zip archive from one of the emails
- File size: 5,317 bytes
- File name: [garbled characters].js
- File description: Extracted JS file from the attached zip archive
- File size: 1,405,704 bytes
- File location: C:\Users\[username]\AppData\Local\Temp\rad012AB.tmp (random hex digits)
- File location: C:\ProgramData\services\csrss.exe
- File description: Initial Shade/Troldesh executable retrieved by the JS file
- File size: 1,635,840 bytes
- File location: C:\Users\[username]\AppData\Local\Temp\0123ABCD.exe (random hex digits)
- File location: C:\ProgramData\Windows\csrss.exe
- File description: Additional malware found on the same infected Windows host
Tor domains from the decryption instructions:
Email address from the decryption instructions:
12 email examples, a pcap of network traffic traffic from an infection, and the associated malware/artifacts are available here.
I checked the 28 URLs I found ending in .jpg for delivering the initial Shade/Troldesh malware binary. 17 of them still returned the ransomware executable. All URLs have been submitted to URLhaus, so hopefully they'll all get taken off-line soon. These URLs will not work if you copy/paste them into a browser, because the servers hosting this malware are looking for the right User-Agent string. You'd have to use a tool like curl to spoof the correct User-Agent string and get the malware.
Russian language malspam pushing Shade/Troldesh ransomware is not anything new. As mentioned earlier, I posted a diary about it back in 2016 and I doubt it ever really disappeared for long. Nor is this malspam limited to Russian malspam. The example I documented in 2017 was from English language malspam. This diary is yet another reminder that the criminals behind this malware remain active and are still trying to infect vulnerable Windows hosts.
brad [at] malware-traffic-analysis.net