Security News
Just weeks after a wave of major in-the-wild zero-day attacks against Exchange Server installations globally, Microsoft is raising a fresh alarm for four new critical security flaws that expose businesses to remote code execution attacks. The four new Exchange Server vulnerabilities were fixed as part of this month's Patch Tuesday bundle and because of the severity of these issues, Microsoft has joined with the U.S. National Security Agency to urge the immediate deployment of the new fixes.
The U.S. Cybersecurity and Infrastructure Security Agency this week published details on additional malware identified on compromised Microsoft Exchange servers, namely China Chopper webshells and DearCry ransomware. The malware operators target Exchange servers through a series of vulnerabilities that were made public on March 3, the same day Microsoft released patches for them.
The 2021 spring edition of Pwn2Own hacking contest concluded last week on April 8 with a three-way tie between Team Devcore, OV, and Computest researchers Daan Keuper and Thijs Alkemade. A zero-click exploit targeting Zoom that employed a three-bug chain to exploit the messenger app and gain code execution on the target system.
The annual Pwn2Own contest features live hacking where top cybersecurity researchers duke it out under time pressure for huge cash prizes. Pwn2Own is a bug bounty program with a twist.
During the first day of Pwn2Own 2021, contestants won $440,000 after successfully exploiting previously unknown vulnerabilities to hack Microsoft's Windows 10 OS, the Exchange mail server, and the Teams communication platform. The first to fall was Microsoft Exchange in the Server category after the Devcore team achieved remote code execution on an Exchange server by chaining together an authentication bypass and a local privilege escalation.
With Azure AD verifiable credentials now available in public preview, Microsoft is collaborating with leading identity verification providers to improve verifiability and secure information exchange. Once verified, these credentials can be used to prove an identity across different organizations to accelerate onboarding of users, secure access to apps or enable a more trustworthy credential recovery experience.
The Department of Homeland Security's Cybersecurity and Infrastructure Security Agency has issued a supplemental directive requiring all federal agencies to identify vulnerable Microsoft Exchange servers. Providing additional direction on the implementation of CISA Emergency Directive 21-02, which on March 3 requested federal agencies to take the necessary steps to disconnect and update Exchange servers, the new directive demands agencies to accelerate the mitigation process.
The Cybersecurity and Infrastructure Security Agency has ordered federal agencies to scan their networks again for any signs of compromised on-premises Microsoft Exchange servers and report their findings within five days. CISA issued another directive ordering federal agencies to urgently update or disconnect their Exchange on-premises servers after Microsoft released security updates for zero-day bugs collectively dubbed ProxyLogon.
The recently patched vulnerabilities in Microsoft Exchange have sparked new interest among cybercriminals, who increased the volume of attacks focusing on this particular vector. While ransomware attacks have increased in frequency in the past six months, cybersecurity company Check Point last week noticed a surge in incidents targeting Microsoft Exchange servers vulnerable to the so-called ProxyLogon critical bugs.
The Black Kingdom/Pydomer ransomware operators have joined the ranks of threat actors targeting the Exchange Server vulnerabilities that Microsoft disclosed in early March. "As of today, we have seen a significant decrease in the number of still-vulnerable servers - more than 92% of known worldwide Exchange IPs are now patched or mitigated. We continue to work with our customers and partners to mitigate the vulnerabilities," Microsoft noted in a March 25 blog post.