Cyber risk and advisory programs that identify security gaps and build strategies to address them.
MDR that provides improved detection, 24/7 threat hunting, end-to-end coverage and most of all, complete Response.
Our team delivers the fastest response time in the industry. Threat suppression within just 4 hours of being engaged.
Visibility and response across your entire Microsoft security ecosystem.
XDR with Machine Learning that eliminates noise, enables real-time detection and response, and automatically blocks threats.
Be protected by the best from Day 1.
24/7 Threat Investigation and Response.
Expert threat hunting, original research, and proactive threat intelligence.
TRU is foundational to our MDR service. No add-ons or additional costs required.
Stop ransomware attacks before they disrupt your business.
Detect and respond to zero-day exploits.
Protect against third-party and supply chain risk.
Adopt a risk-based approach to cybersecurity.
Protect your most sensitive data.
Meet cybersecurity regulatory compliance mandates.
Eliminate misconfigurations and policy violations.
Prevent business disruption by outsourcing MDR.
Meet insurability requirements with MDR.
Defend brute force attacks, active intrusions and unauthorized scans.
Safeguard endpoints 24/7 by isolating and mediating threats to prevent lateral spread.
Enhance investigation and threat detection across multi-cloud or hybrid environments.
Remediate critical misconfigurations, security vulnerabilities and policy violations across cloud and containerized environments.
Detect malicious insider and identity-based behavior leveraging machine learning models.
Our Threat Response Unit (TRU) publishes security advisories, blogs, reports, industry publications and webinars based on its original research and the insights driven through proactive threat hunts.
eSentire is The Authority in Managed Detection and Response Services, protecting the critical data and applications of 2000+ organizations in 80+ countries from known and unknown cyber threats. Founded in 2001, the company's mission is to hunt, investigate and stop cyber threats before they become business disrupting events.
We provide sophisticated cybersecurity solutions for Managed Security Service Providers (MSSPs), Managed Service Providers (MSPs), and Value-Added Resellers (VARs). Find out why you should partner with eSentire, the Authority in Managed Detection and Response, today.
We believe a multi-signal approach is paramount to protecting your complete attack surface. See why eSentire MDR means multi-signal telemetry and complete response.
See how our 24/7 SOC Cyber Analysts and Elite Threat Hunters stop even the most advanced cyberattacks before they disrupt your business.
Choose the right mix of Managed Detection and Response, Exposure Management, and Incident Response services to strengthen your cyber resilience.
Try our interactive tools including the MITRE ATT&CK Tool, the SOC Pricing Calculator, the Cybersecurity Maturity Assessment, and our MDR ROI Calculator.
Read the latest security advisories, blogs, reports, industry publications and webinars published by eSentire's Threat Response Unit (TRU).
See why 2000+ organizations count on eSentire to build resilience and prevent business disruption.
THE THREAT
Exploitation of the Microsoft on premise Exchange vulnerabilities (announced March 2nd, 2021) is more widespread than previously reported. eSentire has observed reports of multiple APT groups exploiting these vulnerabilities in attack campaigns. Attacks targeting these vulnerabilities have been ongoing since at least January 2021. It is critical that Microsoft Exchange Server versions 2010, 2013, 2016, and 2019 are updated. All vulnerable servers are at a high risk of exploitation by advanced threat actor groups. Because exploitation occurred prior to patch release, internet-exposed Microsoft Exchange servers should be reviewed for any evidence of exploitation.
What we’re doing about it
What you should do about it
Additional information
The eSentire Threat Intelligence team has observed reports which indicate more widespread exploitation of these vulnerabilities than initially believed. Customers are strongly advised to prioritize patching vulnerable Exchange servers exposed to the Internet. Additionally, customers are advised to work with the eSentire SOC to review these systems and remediate any identified threats resulting from these vulnerabilities.
eSentire teams are actively developing detection for this threat and performing retroactive queries across our customers in parallel. eSentire recommends customers ensure eSentire services are monitoring impacted systems and, out of an abundance of caution, review on-premise Exchange servers for evidence of exploitation per Microsoft’s guidance (Microsoft has automated these checks with the PowerShell script available here). Customers should coordinate with eSentire’s SOC on any positive identification from these activities.
Confirmed vulnerable on-premises Microsoft Exchange Servers:
Microsoft Exchange Server 2010 has reached End of Life (EoL) status but received emergency patches. Organizations are strongly recommended to discontinue the use of all EoL products in favor of actively supported alternatives.
Exploited Vulnerabilities:
CVE-2021-26855 (CVSS Score: 9.1/10) – Is a server-side request forgery (SSRF) vulnerability in Microsoft Exchange, which allows a threat actor to send an arbitrary HTTP request and authenticate as the Exchange server.
CVE-2021-26857 (CVSS Score: 7.8/10) – Is an insecure deserialization vulnerability in the Unified Messaging service and requires administrator privileges or the use of another vulnerability to exploit. This vulnerability gave HAFNIUM the controls to run code as SYSTEM on an exchange server.
CVE-2021-26858 / CVE-2021-27065 (CVSS Score: 7.8/10) – Are post-authentication arbitrary file write vulnerabilities in Microsoft Exchange and require either compromising an admin’s credentials or the use of CVE-2021-26855.
According to public reports, at least four separate APT groups have been confirmed to have exploited these vulnerabilities. Known threat actor groups include Hafnium, APT27 (ie. LuckyMouse), Tick (ie. Bronze Butler), and Calypso. The majority of victims are located in the United States, but limited activity was identified in 21 other countries. Specific victim details and attacker goals are currently not known. eSentire security teams will continue to track this event going forward.
References:
[1] https://www.esentire.com/security-advisories/multiple-0-day-exploits-targeting-on-premise-exchange-versions
[2] https://msrc-blog.microsoft.com/2021/03/02/multiple-security-updates-released-for-exchange-server/
[3] https://www.microsoft.com/security/blog/2021/03/02/hafnium-targeting-exchange-servers/
[4] https://www.volexity.com/blog/2021/03/02/active-exploitation-of-microsoft-exchange-zero-day-vulnerabilities/
[5] https://www.reddit.com/r/msp/comments/lwmo5c/mass_exploitation_of_onprem_exchange_servers/
[6] https://twitter.com/ESETresearch/status/1366862951156695047