NEWS

Exploits on Organizations Worldwide Tripled after Microsoft's Revelation of Four Zero-days

By VARINDIA - 2021-03-15

Following the revelation of four zero-day vulnerabilities currently affecting Microsoft Exchange Server, Check Point Research (CPR) discloses its latest observations on exploitation attempts against organizations that it tracks worldwide.

Adi Ikan, Head of Network Research and Protection

Lotem Finkelsteen, the head of Threat Intelligence

Yaniv Balmas, Check Point’s Head of Cyber Research

Sagi Tzadik, Security Researcher

· CPR has seen hundreds of exploit attempts against organizations worldwide

· In the past 72 hours alone, CPR has observed that the number exploitation attempts multiplied by more than 6 times

· The country most attacked has been The United States (21% of all exploit attempts), followed by The Netherlands (12%) and Turkey (12%).

· Most targeted industry sector has been Government/Military (27% of all exploit attempts), followed by Manufacturing (22%), and then Software vendors (9%).

Since the recently disclosed vulnerabilities on Microsoft Exchange Servers, a full race has started amongst hackers and security professionals. Global experts are using massive preventative efforts to combat hackers who are working day-in and day-out to produce an exploit that can successfully leverage the remote code execution vulnerabilities in Microsoft Exchange.

CPR has outlined the disclosed vulnerabilities, the targeted organizations by country and industry, and then recommendations to prevent the attacks, which are yet to come.

Current attack attempts in numbers

The country most attacked has been The United States (21% of all exploit attempts), followed by The Netherlands (12%) and Turkey (12%).

Most targeted industry sector has been Government/Military (27% of all exploit attempts), followed by Manufacturing (22%), and then Software vendors (9%).

Behind-the-scenes of the Zero Days

On March 3, 2021 Microsoft released an emergency patch for its Exchange Server product, the most popular mail server worldwide. All incoming and outgoing emails, calendar invitations and virtually anything accessed within Outlook goes through the Exchange server.

Orange Tsai (Cheng-Da Tsai) from DEVCORE, a security firm based in Taiwan, reported two vulnerabilities in January. Unware of the full magnitude of these findings, Microsoft was prompted to further investigate their Exchange server. The investigation uncovered five more critical vulnerabilities.

The vulnerabilities allow an attacker to read emails from an Exchange server without authentication or accessing an individual’s email account. Further vulnerability chaining enables attackers to completely take over the mail server itself.

Once an attacker takes over the Exchange server, they can open the network to the internet and access it remotely. As many Exchange servers have internet exposer (specifically Outlook Web Access feature) and are integrated within the broader network, this poses a critical security risk for millions of organizations.

Orange Tsai (Cheng-Da Tsai) teaser for pre-authentication remote code execution chain on Twitter, Jan 05,2021.

What organizations are at risk?

If your organization’s Microsoft Exchange server is exposed to the internet, and has not been updated with the latest patches nor protected by a third party software such as Check Point, then you should assume the server is completely compromised. Compromised servers could enable an unauthorized attacker to extract your corporate emails and execute malicious code inside your organization with high privileges.

Technical Explanation

· CVE-2021-26855 - is a server-side request forgery (SSRF) vulnerability in Exchange which allows the attacker to send arbitrary HTTP requests and authenticate as the Exchange server.

· CVE-2021-26857 - is an insecure deserialization vulnerability in the Unified Messaging service. Insecure deserialization is where untrusted user-controllable data is desterilized by a program. Exploiting this vulnerability gives HAFNIUM the ability to run code as SYSTEM on the Exchange server. This requires administrator permission or another vulnerability to exploit.

· CVE-2021-26858 - is a post-authentication arbitrary file write vulnerability in Exchange. If HAFNIUM could authenticate with the Exchange server then they could use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.

· CVE-2021-27065 - is a post-authentication arbitrary file write vulnerability in Exchange. If HAFNIUM could authenticate with the Exchange server then they could use this vulnerability to write a file to any path on the server. They could authenticate by exploiting the CVE-2021-26855 SSRF vulnerability or by compromising a legitimate admin’s credentials.

Since the disclosure, CPR has received questions regarding the identity of the attackers, their motivation and the wide context of recent major hacks.

According to Lotem Finkelsteen, Manager of Threat Intelligence, Check Point Software,

“If your organization’s Microsoft Exchange server is exposed to the internet, and if it has not been updated with the latest patches, nor protected by a third party software, then you should assume the server is completely compromised. In this attack, as in Sunburst, a particularly common platform was used as a front door for covert entry and prolonged stay within the network. Right now, the purpose of the attack and what cybercriminals wanted within the network is still unknown. What we do know is that compromised servers could enable an unauthorized attacker to extract your corporate emails and execute malicious code inside your organization with high privileges. Organizations who are at risk should not only take preventive actions on their Exchange, but also scan their networks for live threats and assess all assets.”

Prevent Future Attacks and Remain Protected

Here are Check Point’s recommendations to prevent future attacks and remain protected:

· Patch – immediately update all Microsoft Exchange Servers to the latest patched versions available by Microsoft. This update is not automatic and you are expected to perform it manually.

· Threat Prevention protections - Check Point provides comprehensive security coverage to the vulnerabilities reported by Microsoft with the following Threat Prevention protections:

IPS

o CVE-2021-26855 - CPAI-2021-0099

o CVE-2021-26857 - CPAI-2021-0107

o CVE-2021-26858 - CPAI-2021-0107

o CVE-2021-27065 - CPAI-2021-0099

Threat Emulation

o Trojan.WinsCVE-2021-27065.A

Anti-Virus

o HAFNIUM.TC. XXX

o Trojan.Win32.Hafnium.TC.XXX

Check Point Harmony Endpoint (formally known as SandBlast Agent)

o Behavioral.Win.SuspExchange.A