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Visualizing a String of Paerls

Researchers from the Cisco Talos Security Intelligence and Research Team recently discovered an elaborate attack dubbed the String of Paerls. The attack, a combined spearphishing and exploit attempt, was able to bypass most antivirus engines and used a targeted phishing email that included a malicious Word document attachment. Upon opening the Word attachment, a macro downloaded and launched an executable on the victim’s machine, which then called out to command and control servers.

In the graphic below you can see an illustration of each of the major steps of the attack. A common thread is that Cisco security provides protection against attacks like this one using the approach of integrated threat defense. Specifically, Advanced Malware Protection tools were used throughout the discovery and analysis process to expose the exploit.

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For a complete play-by-play of this attack, read the String of Paerls blog post from Talos. For more about integrated threat defense in our products, see the new Cisco ASA with FirePOWER Services.

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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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Threat Spotlight: “A String of Paerls”, Part 2, Deep Dive

July 8, 2014 at 7:28 am PST

This post has been coauthored by Joel EslerCraig WilliamsRichard HarmanJaeson Schultz, and Douglas Goddard 

In part one of our two part blog series on the “String of Paerls” threat, we showed an attack involving a spearphish message containing an attached malicious Word doc. We also described our methodology in grouping similar samples based on Indicators of Compromise: static and dynamic analysis indicators. In this second part of the blog series we will cover the malicious documents and malicious executables. For the technical deep dive see the write up on the VRT blog here.

 

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Threat Spotlight: A String of ‘Paerls’, Part One

June 30, 2014 at 7:00 am PST

This post was co-authored by Jaeson SchultzJoel Esler, and Richard Harman

Update 7-8-14: Part 2 can be found hereVRT / TRAC

This is part one in a two-part series due to the sheer amount of data we found on this threat and threat actor. This particular attack was a combined spearphishing and exploit attempt. As we’ve seen in the past, this can be a very effective combination.

In this specific example the attackers targeted a feature within Microsoft Word — Visual Basic Scripting for Applications. While basic, the Office Macro attack vector is obviously still working quite effectively.  When the victim opens the Word document, an On-Open macro fires, which results in downloading an executable and launching it on the victim’s machine. This threat actor has particularly lavish tastes.  This threat actor seem to target high-profile, money-rich industries such as banking, oil, television, and jewelry.

Discovering the threat

The VRT has hundreds of feeds of raw threat intelligence, ranging from suspicious URLs, files, hashes, etc.  We take that intelligence data and apply  selection logic to it to identify samples that are worthy of review.  Using various methods from machine learning to dynamic sandbox analysis, we gather details about the samples -- producing indicator of  compromise (IOC), and alerts made up of multiple IOCs.

During our analysis we took the last 45 days’ worth of samples, and clustered them together based on a matching set of alert criteria.  This process reduced over a million detailed sample reports to just over 15 thousand sample clusters that exhibit similar behavior.  Using this pattern of similar behavior, we were capable of identifying families of malware.  This led us to discover a Microsoft Word document that downloaded and executed a secondary sample, which began beaconing to a command and control server.

The Malicious Word documents & Associated Phishing campaign

The attacks we uncovered are an extremely targeted spear phish in the form of an invoice, purchase order, or receipt, written specifically for the recipient.  For instance, the following is an example message we observed that purportedly came from “Maesrk”, the shipping company.

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Read More »

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Watering Hole Attacks an Attractive Alternative to Spear Phishing

“Watering Hole” attacks, as evidenced by the recent attack involving the U.S. Department of Labor, are becoming increasingly popular as alternatives to attacks such as Spear Phishing. In a “Watering Hole” attack, the attacker compromises a site likely to be visited by a particular target group, rather than attacking the target group directly. Eventually, someone from the targeted group visits the “trusted” site (A.K.A. the “Watering Hole”) and becomes compromised.

Cisco identified suspicious GET requests made to the www.sellagreement.com, a malicious site which was recently linked with the Department of Labor attack. According to the evidence we have, the sites www.kforce.com and www.sbc.net were among those compromised during this attack. The webpages that were serving malicious content from these sites were mostly job-search related, but several requests to www.sellagreement.com lacked a “Referrer:” HTTP header entirely. Read More »

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