Servers from China behind 282-fold increase in IIS attacks

IIS attacks showed a 782-fold increase, from 2,000 to 1.7 million, in the second quarter of this year compared to the quarter before.

Biotechnology, accounting, real estate, marketing and construction sectors were industries most seriously affected.

The most common execution tactic technique observed around endpoint solutions was the use of PowerShell (32%), followed by VBA scripting (21%). Of the PowerShell-based attacks observed, 83% used obfuscated command lines intended to hide their intentions.

The findings come courtesy of a new threat report from eSentire, Inc.

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The report found that most sources targeting IIS web servers originated from China-based IP addresses. According to Shodan, there are 3.5 million IIS web servers exposed (with 1 million in China). The compromised servers largely originated from Tencent and Alibaba.

eSentire also said that there was an “interesting collection of operating systems among the attacking infrastructure involved.” More than 400 of the attacking IPs had Shodan records indicating they were Windows machines (including XP, 7, 8, 2008, and 2012). Additionally, nearly 350 FTP servers and over 100 mail servers were reported; there were also VPN servers, MikroTik devices (reported as bandwidth-testing servers), Kangle, Squid, Jetty and a handful of lesser-known web service technologies.

“IIS is a popular web server, with prevalence in the US and China,” explained Kerry Bailey, CEO, eSentire.

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Bailey suggested that “organisations using web servers need to make sure they monitor for these vulnerabilities and update or patch as necessary.

“Oracle WebLogic is another web server that saw a lot of attacks and we’ve seen Apache attacks reported too.

“Web servers are exposed de facto, which makes them a primary target, and we saw continued attacks against IIS continue in Q3 2018.

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“IIS patches for earlier versions, like 6.0, are available. Otherwise, users should consider updating to more recent versions of the web server.”

The report also found that:

  • Emotet was the most frequently observed malware due to numerous version updates and feature additions since it was first reported in 2014.
  • The use of obfuscated PowerShell commands increased 50% from last quarter, partly due to contributions by Emotet.
  • Four observed exploit campaigns stood out targeting IIS, Drupal, WebLogic servers, and GPON routers. GPON home routers were attacked after the PoC code release (eSentire saw 5K detections total, with volume peaking ‪on May 12‬). eSentire continues to see home router exploits through Q3.

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Michael Baxter

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