Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Vulnerabilities / Threats

11/26/2019
03:35 PM
Connect Directly
Twitter
LinkedIn
RSS
E-Mail
50%
50%

'Dexphot': A Sophisticated, Everyday Threat

Though the cryptominer has received little attention, it exemplifies the complexity of modern malware, Microsoft says.

Malware threats don't have to have a high profile to be extremely dangerous. Sometimes, even the more common strains can pose big problems.

A case in point is "Dexphot," a cryptomining tool that Microsoft has been tracking for the past year and which the company says exemplifies the complexity and fast-evolving nature of even the more everyday threats that organizations now face.

Dexphot first surfaced in October 2018 and has since then infected tens of thousands of systems but has received little of the attention that some malware threats receive. Microsoft researchers initially observed the malware attempting to deploy files that changed literally every 20 to 30 minutes on thousands of devices.

The company's subsequent analysis of the polymorphic malware showed it employs multiple layers of obfuscation, encryption, and randomized file names to evade detection.

Like many other modern malware tools, Dexphot was designed to run entirely in memory. It also hijacked legitimate processes so defenders couldn't easily detect its malicious activity. When Dexphot finally did get installed on a system, it used monitoring services and a list of scheduled tasks to reinfect systems when defenders tried to remove the malware.

The authors of the Dexphot have kept upgrading and tweaking the malware in the year since it was first detected, according to Microsoft. Most of the changes have been designed to help the malware evade detection.

What makes Dexphot especially troublesome for defenders is the malware's use of legitimate processes and services for carrying out its activity. In fact, except for the installer that is used to drop the malware on a system, all other processes that Dexphot uses are legitimate system processes, according to a Microsoft blog post.

Among them is a process for running programs in DLL files (rundll32[.]exe), another for extracting files from ZIP archives (unzip[.]exe), one for scheduling tasks (schtasks[.]exe), and PowerShell for task automation.

Dexphot also employs "process hollowing," a tactic in which the malware is hidden inside a legitimate process such as svchost[.]exe, tracert[.]exe, and setup[.]exe. Malware hidden in this manner can be hard to find, which is why threat actors have increasingly begun using it, Microsoft says. "This method has the additional benefit of being fileless," according to the blog post. "Not only is it harder to detect the malicious code while it's running, it's harder to find useful forensics after the process has stopped."

Malware employing such living-off-the-land tactics have become a big and growing problem for enterprise organizations. A recent report from Rapid7 identified several legitimate processes that attackers are increasingly using to hide malicious activity. Rapid7 found that PowerShell is easily the most abused executable. Other popular processes include cmd[.]exe; ADExplorer[.]exe; procdump64[.]exe, rudll32[.]exe, and schtasks[.]exe.

"The continued focus on using built-in Windows functions allow the attackers to persist mostly unnoticed after their initial bypass of security controls," Rapid7 notes in its report. Since few security tools are designed to look for threats in administrative tools and legitimate processes, the vendor explains, organizations need to monitor for known usage patterns for Windows utilities used by attackers.

Related Content:

Check out The Edge, Dark Reading's new section for features, threat data, and in-depth perspectives. Today's top story: "Home Safe: 20 Cybersecurity Tips for Your Remote Workers."

Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year ... View Full Bio

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
SOC 2s & Third-Party Assessments: How to Prevent Them from Being Used in a Data Breach Lawsuit
Beth Burgin Waller, Chair, Cybersecurity & Data Privacy Practice , Woods Rogers PLC,  12/5/2019
Navigating Security in the Cloud
Diya Jolly, Chief Product Officer, Okta,  12/4/2019
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
Write a Caption, Win a Starbucks Card! Click Here
Latest Comment: "This is the last time we hire Game of Thrones Security"
Current Issue
Navigating the Deluge of Security Data
In this Tech Digest, Dark Reading shares the experiences of some top security practitioners as they navigate volumes of security data. We examine some examples of how enterprises can cull this data to find the clues they need.
Flash Poll
Rethinking Enterprise Data Defense
Rethinking Enterprise Data Defense
Frustrated with recurring intrusions and breaches, cybersecurity professionals are questioning some of the industrys conventional wisdom. Heres a look at what theyre thinking about.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2019-4428
PUBLISHED: 2019-12-09
IBM Watson Assistant for IBM Cloud Pak for Data 1.0.0 through 1.3.0 is vulnerable to cross-site scripting. This vulnerability allows users to embed arbitrary JavaScript code in the Web UI thus altering the intended functionality potentially leading to credentials disclosure within a trusted session....
CVE-2019-4611
PUBLISHED: 2019-12-09
IBM Planning Analytics 2.0 is vulnerable to cross-site scripting. This vulnerability allows users to embed arbitrary JavaScript code in the Web UI thus altering the intended functionality potentially leading to credentials disclosure within a trusted session. IBM X-Force ID: 168519.
CVE-2019-4612
PUBLISHED: 2019-12-09
IBM Planning Analytics 2.0 is vulnerable to malicious file upload in the My Account Portal. Attackers can make use of this weakness and upload malicious executable files into the system and it can be sent to victim for performing further attacks. IBM X-Force ID: 168523.
CVE-2019-4621
PUBLISHED: 2019-12-09
IBM DataPower Gateway 7.6.0.0-7 throug 6.0.14 and 2018.4.1.0 through 2018.4.1.5 have a default administrator account that is enabled if the IPMI LAN channel is enabled. A remote attacker could use this account to gain unauthorised access to the BMC. IBM X-Force ID: 168883.
CVE-2019-19230
PUBLISHED: 2019-12-09
An unsafe deserialization vulnerability exists in CA Release Automation (Nolio) 6.6 with the DataManagement component that can allow a remote attacker to execute arbitrary code.