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.

Risk

3/25/2021
05:50 PM
50%
50%

CISA Adds Two Web Shells to Exchange Server Guidance

Officials update mitigation steps to include two new Malware Analysis Reports identifying Web shells seen in Exchange Server attacks.

The Department of Homeland Security's Cybersecurity and Infrastructure Security Agency (CISA) today updated its guidance for ongoing Microsoft Exchange Server exploits to include two new Malware Analysis Reports (MARs). 

Related Content:

Inside the Web Shell Used in the Microsoft Exchange Server Attacks

Special Report: Building an Effective Cybersecurity Incident Response Team

New From The Edge: In Secure Silicon We Trust

Each of these reports, now included in CISA's full "Mitigate Microsoft Exchange Server Vulnerabilities" alert, identifies a Web shell seen in post-compromised Microsoft Exchange servers. CISA has also updated seven existing MARs to include YARA rules developed by CISA to help organizations detect the malware seen so far in these attacks. 

All of the MARs shared so far focus on China Chopper, a Web shell commonly seen in the attacks. After exploiting an Exchange Server vulnerability to gain initial access, an attacker can use China Chopper to remotely execute operating system commands and conduct activities such as uploading and executing tools, pivoting to other systems, and exfiltrating data. 

Prior to today, CISA had already updated its guidance to detail seven China Chopper Web shells; today's addition brings it to nine in total. Officials note this is not an all-inclusive list of the Web shells attackers are using. 

Read more details here.

Dark Reading's Quick Hits delivers a brief synopsis and summary of the significance of breaking news events. For more information from the original source of the news item, please follow the link provided in this article. View Full Bio
 

Recommended Reading:

Comment  | 
Print  | 
More Insights
Comments
Newest First  |  Oldest First  |  Threaded View
News
Inside the Ransomware Campaigns Targeting Exchange Servers
Kelly Sheridan, Staff Editor, Dark Reading,  4/2/2021
Commentary
Beyond MITRE ATT&CK: The Case for a New Cyber Kill Chain
Rik Turner, Principal Analyst, Infrastructure Solutions, Omdia,  3/30/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
2021 Top Enterprise IT Trends
We've identified the key trends that are poised to impact the IT landscape in 2021. Find out why they're important and how they will affect you today!
Flash Poll
How Enterprises are Developing Secure Applications
How Enterprises are Developing Secure Applications
Recent breaches of third-party apps are driving many organizations to think harder about the security of their off-the-shelf software as they continue to move left in secure software development practices.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2021-30481
PUBLISHED: 2021-04-10
Valve Steam through 2021-04-10, when a Source engine game is installed, allows remote authenticated users to execute arbitrary code because of a buffer overflow that occurs for a Steam invite after one click.
CVE-2021-20020
PUBLISHED: 2021-04-10
A command execution vulnerability in SonicWall GMS 9.3 allows a remote unauthenticated attacker to locally escalate privilege to root.
CVE-2021-30480
PUBLISHED: 2021-04-09
Zoom Chat through 2021-04-09 on Windows and macOS allows certain remote authenticated attackers to execute arbitrary code without user interaction. An attacker must be within the same organization, or an external party who has been accepted as a contact. NOTE: this is specific to the Zoom Chat softw...
CVE-2021-21194
PUBLISHED: 2021-04-09
Use after free in screen sharing in Google Chrome prior to 89.0.4389.114 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
CVE-2021-21195
PUBLISHED: 2021-04-09
Use after free in V8 in Google Chrome prior to 89.0.4389.114 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.