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Dridex Is Back, then it’s gone again

This post was authored by Armin Pelkmann and Earl Carter.

Talos Security Intelligence and Research Group noticed a reappearance of several Dridex email campaigns, starting last week and continuing into this week as well. Dridex is in a nutshell, malware designed to steal your financial account information. The attack attempts to get the user to install the malicious software on their system through an until lately, rarely exploited attack vector: Microsoft Office Macros. Recently, we noticed a resurgence of macro abuse. If macros are not enabled, social engineering techniques are utilized to try to get the user to enable them. Once the malware is installed on the system, it is designed to steal your online banking credentials when you access your banking site from an infected system.

Talos analyzed three separate campaigns in the last days, all distinguishable from their subject lines. Read More »

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Help! My IP Address Has Been Hijacked!

SpamCop is a free, community-based spam email reporting service provided by Cisco. SpamCop analyzes reported spam, and extracts details about the sending IP, the URLs contained in the spam, and the networks over which the spam message has transited. This information is used to create the SpamCop Block List (SCBL). The SCBL a list of IP addresses believed to be sending Unsolicited Bulk Email.

As part of its service, each week SpamCop sends millions of email messages to notify network administrators about malicious activity that is observed occurring on their networks. SpamCop receives all types of replies in response to our notification emails. Many times recipients of SpamCop’s notifications will reply to SpamCop and claim, “we did not send the spam”. The SpamCop Deputies responsible for following up on these replies have heard every excuse under the sun. For them, “we did not send the spam” is the spam block list equivalent of “the dog ate my homework.”

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Snowshoe Spam Attack Comes and Goes in a Flurry

This post is co-authored by Jaeson Schultz and Craig Williams.

Every so often, we observe certain spam campaigns that catch our interest. On August 15, we observed a particular spam campaign that caught our attention because it was using “snowshoe” spam techniques combined with PDF exploitation. While neither of these techniques are new, we have seen a growing trend involving snowshoe spam and we wanted to explain why the bad guys seem to be moving in that direction with a real world example. As you can see from the chart below, we’ve seen the amount of snowshoe spam double since November of 2013.

Snowshoe Spam Chart

Snowshoe spam can be a challenge for some anti-spam detection techniques because it typically uses multiple IP addresses with very low spam volume per IP address. Depending on how an anti-spam technology works, this can cause severe problems with detection. Typically technologies that use multiple defensive layers of protection, like Cisco’s ESA, are much more successful at combating snowshoe spam. We’ve previously discussed these tactics in a previous blog post.

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Big Data: Observing a Phishing Attack Over Years

google_drive_attack

Overview

Phishing attacks use social engineering in an attempt to lure victims to fake websites. The websites could allow the attacker to retrieve sensitive or private information such as usernames, passwords, and credit card details. Attacks of this kind have been around since 1995, evolving in sophistication in order to increase their success rate. Up until now, phishing attacks were generally viewed as isolated events that were dealt with on a case-by-case basis. The dawn of big data analysis in computer security allows us to store data indefinitely and watch the changes and growth of attacks over long periods of time. In 2012, we began tracking a sophisticated phishing campaign that is still going strong.

 

The Target

Google, one of the largest players in the cloud business, offers dozens of free cloud services: Google Email, Google Drive, Google Docs, Google Analytics, YouTube, etc. To enable easy access across all of these properties, Google built what they call, “One account. All of Google.”   Read More »

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Walking in a Winter Wonderland

It is not uncommon to see an anti-spam system catch >99% of the spam passing through it. Most of the best anti-spam systems catch >99.9% of spam. In this environment, spammers try just about anything to evade spam filters. Some spammers believe that blasting at high volume is the key to success. Others believe complete randomization of the message headers will confuse the anti-spam system. Still others take a minimalist approach, sending only a URL in the body. As anti-spam systems close gaps in their coverage, spammers are forced to find new tricks (or resort to variations on old tricks). It’s an arms race.

Screen-Shot-2014-05-24-at-5.24.29-AM-300x224One spam technique in particular is attracting more and more spammers. This technique is known in the email industry as “snowshoe” spam. Snowshoes are footwear that allows a person to walk over deep snow by distributing their weight over a larger surface area, thus preventing the wearer’s foot from sinking. But what do snowshoes have to do with unsolicited bulk email? In the email world “snowshoe” spam is unsolicited bulk email that is sent using a large number of IP addresses, and at a low message volume per IP address.

Cisco’s worldwide sensor network records details about a substantial quantity of spam. We analyze this large dataset for trends among senders. Below is a breakdown of spam by sender type. Note that the volume of snowshoe spam has more than doubled since November 2013.

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Spam broken down by Sender Type

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