spam

1 min read

By examining sextortion spam campaigns in detail, our researchers were able to understand how criminals operate, and to see why users were tricked into sending them bitcoin despite empty threats.

1 min read

This post was written by Jaeson Schultz. Introduction Over the past five years the Necurs botnet has established itself as the largest purveyor of spam worldwide. Necurs is responsible for emailing massive amounts of banking malware, ransomware, dating spam, pump-n-dump stock scams, work from home schemes, and even cryptocurrency wallet credential phishing. Necurs sends so much […]

1 min read

This post was authored by Alex Chiu, Warren Mercer, and Jaeson Schultz.  Sean Baird and Matthew Molyett contributed to this post. Back in May, the Necurs spam botnet jettisoned Locky ransomware in favor of the new Jaff ransomware variant. However, earlier this month Kaspersky discovered a vulnerability within Jaff which allowed them to create a decryptor. […]

1 min read

This post was authored by Nick Biasini Throughout the majority of 2016, Locky was the dominant ransomware in the threat landscape.  It was an early pioneer when it came to using scripting formats Windows hosts would natively handle, like .js, .wsf, and .hta. These scripting formats acted as a vehicle to deliver the payload via […]

1 min read

This post is authored by Paul Rascagneres with contributions from Alex McDonnell Executive Summary Talos has discovered a new spam campaign used to infect targets with the well known  Loki Bot stealer. The infection vector is an RTF document abusing an old exploit (CVE-2012-1856), however the most interesting part is the effort put into the […]

1 min read

This post authored by Nick Biasini with contributions from Jaeson Schultz Locky has been a devastating force for the last year in the spam and ransomware landscape. The Locky variant of ransomware has been responsible for huge amounts of spam messages being sent on a daily basis. The main driver behind this traffic is the […]

1 min read

This blog post was authored by Jakob Dohrmann, David Rodriguez, and Jaeson Schultz. The Cisco Talos and Umbrella research teams are deploying a distributed hailstorm detection system which brings together machine learning, stream processing of DNS requests and the curated Talos email corpus. Talos has discussed snowshoe spam before. Traditional snowshoe spam campaigns are sent […]

1 min read

This post authored by Nick Biasini Talos is constantly monitoring the threat landscape including the email threat landscape. Lately this landscape has been dominated with Locky distribution. During a recent Locky vacation Talos noticed an interesting shift in file types being used to distribute another well known malware family, Fareit. We’ve discussed Fareit before, it’s […]

1 min read

Talos have observed a large uptick in the Zepto ransomware and have identified a method of distribution for the Zepto ransomware, Spam Email. Locky/Zepto continue to be well known ransomware variants and as such we will focus on the spam email campaign. We found 137,731 emails in the last 4 days using a new attachment […]