Cisco Threat Research Blog

This blog was authored by Warren Mercer and Paul Rascagneres with contributions from Matthew Molyett.

Executive Summary

A few weeks ago, Talos published research on a Korean MalDoc. As we previously discussed this actor is quick to cover their tracks and very quickly cleaned up their compromised hosts. We believe the compromised infrastructure was live for a mere matter of hours during any campaign. We identified a new campaign, again leveraging a malicious Hangul Word Processor (HWP) document. After analyzing the final payload, we determined the winner was… a Remote Administration Tool, which we have named ROKRAT.

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Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed between March 24 and March 31. As with previous round-ups, this post isn’t meant to be an in-depth analysis. Instead, this post will summarize the threats we’ve observed by highlighting key behavior characteristics, indicators of compromise, and how our customers are automatically protected from these threats.

As a reminder, the information provided for the following threats in this post is non-exhaustive and current as of date of publication. Detection and coverage for the following threats is subject to updates pending additional threat or vulnerability analysis. For the most current information, please refer to your FireSIGHT Management Center, Snort.org, or ClamAV.net.

This post authored by Nick Biasini with contributions from Edmund Brumaghin and Alex Chiu

The last time Talos discussed Sundown it was an exploit kit in transition. Several of the large exploit kits had left the landscape and a couple of strong contenders remain. Sundown was one of the kits still active and poised to make a move, but lacked a lot of the sophistication of the other large kits and had lots of easy identifiers throughout its infection chain. Most of these identifiers have been stripped, new exploits added, and Talos was able to uncover an interesting campaign focused around the bulk purchase of expiring domains through auctions commonly held within the domain resellers market.

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Most people don’t give much thought to what happens when you connect to your bank’s website or log in to your email account. For most people, securely connecting to a website seems as simple as checking to make sure the little padlock in the address bar is present. However, in the background there are many different steps that are taken to ensure you are safely and securely connecting to the websites that claim they are who they are. This process includes certificate validation, or making sure that the servers that users are connecting to present “identification” showing they are legitimate. This helps to protect users from fraudulent servers that might otherwise steal sensitive information.

Due to the sensitive nature of this process, software vulnerabilities that adversely impact the security of certificate validation could have major consequences. Unfortunately, digital systems are complex and bugs are an inevitable reality in software development. Identifying vulnerabilities and responsibly disclosing them improves the security of the internet by eliminating potential attack vectors. Talos is committed to improving the overall security of the internet and today we are disclosing TALOS-2017-0296 (CVE-2017-2485), a remote code execution vulnerability in the X.509 certificate validation functionality of Apple macOS and iOS. This vulnerability has been responsibly disclosed to Apple and software updates have been released that address this issue for both macOS and iOS.

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Today, Talos is publishing a glimpse into the most prevalent threats we’ve observed over the past week. As with previous round-ups, this post isn’t meant to be an in-depth analysis. Instead, this post will summarize the threats we’ve observed by highlighting key behavior characteristics, indicators of compromise, and how our customers are automatically protected from these threats.

As a reminder, the information provided for the following threats in this post is non-exhaustive and current as of date of publication. Detection and coverage for the following threats is subject to updates pending additional threat or vulnerability analysis. For the most current information, please refer to your FireSIGHT Management Center, Snort.org, or ClamAV.net.

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 generation of the RTF. The document contains several malformations designed to defeat security engines and parsers. The attacker has gone out of their way to attempt to evade content inspection devices like AV or network security devices. According to VirusTotal, the initial detection rate of a malicious RTF document recovered from a recent spam campaign is only 3 out of 45 available engines.

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Overview

LabVIEW is a system design and development platform released by National Instruments. The software is widely used to create applications for data acquisition, instrument control and industrial automation. Talos is disclosing the presence of a code execution vulnerability and a memory corruption vulnerability which can be triggered by opening specially crafted VI files, the proprietary file format used by LabVIEW.

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The post was authored by Sean Baird, Edmund Brumaghin and Earl Carter, with contributions from Jaeson Schultz.

Executive Summary

The Necurs botnet is the largest spam botnet in the world. Over the past year it has been used primarily for the distribution of Locky ransomware and Dridex. Earlier this year, we wrote about how the Necurs botnet went offline and seemingly disappeared, taking most of the high volume Locky malspam with it. Talos recently identified a significant increase in the amount of spam emails originating from the Necurs botnet, indicating that it may have come back to life, but rather than distributing malware in the form of malicious attachments, it appears to have shifted back to penny stock pump-and-dump messages. This is not the first time that Necurs has been used to send high volume pump-and-dump emails. In analyzing previous telemetry data associated with these campaigns, we identified a similar campaign on December 20, 2016 shortly before the Necurs botnet went offline for an extended period. This strategic divergence from the distribution of malware may be indicative of a change in the way that attackers are attempting to economically leverage this botnet.

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