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
FluBot Malware's Rapid Spread May Soon Hit US Phones
Kelly Sheridan, Staff Editor, Dark Reading,  4/28/2021
Slideshows
7 Modern-Day Cybersecurity Realities
Steve Zurier, Contributing Writer,  4/30/2021
Commentary
How to Secure Employees' Home Wi-Fi Networks
Bert Kashyap, CEO and Co-Founder at SecureW2,  4/28/2021
Register for Dark Reading Newsletters
White Papers
Video
Cartoon Contest
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-2021-31755
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setmac allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31756
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /gofrom/setwanType allows attackers to execute arbitrary code on the system via a crafted post request. This occurs when input vector controlled by malicious attack get copie...
CVE-2021-31757
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setVLAN allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31758
PUBLISHED: 2021-05-07
An issue was discovered on Tenda AC11 devices with firmware through 02.03.01.104_CN. A stack buffer overflow vulnerability in /goform/setportList allows attackers to execute arbitrary code on the system via a crafted post request.
CVE-2021-31458
PUBLISHED: 2021-05-07
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit Reader 10.1.1.37576. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handlin...