Over 60,000 Online Exchange Servers Unpatched for RCE Vulnerability ProxyNotShell

One of the two security flaws targeted by ProxyNotShell exploits, CVE-2022-41082 RCE vulnerability, has not been patched on more than 60,000 Microsoft Exchange servers, as a result, they are exposed online.

Another flaw that is in question has been tracked as CVE-2022-41080. A series of targeted attacks were employed by threat actors to exploit the ProxyNotShell zero-day vulnerabilities first disclosed in September.

It has been reported that almost 70,000 Microsoft Exchange servers are at risk of proxyNotShell attacks, in accordance with a recent tweet from security researchers at the Shadowserver Foundation.

As of recent data, 60,865 Exchange servers were detected as vulnerable on January 2nd, and this count is a decreased figure which is fallen from 83,946 in mid-December.

Vulnerable Exchange Versions

As a collective term, ProxyNotShell is the combination of these two security bugs. Apart from this, it has been found that these flaws affect the Exchange Server:-

  • 2013
  • 2016
  • 2019

The x_owa_version header was the basis for the experts’ assessment. Listed below are the Exchange versions that are vulnerable to these flaws (CVE-2022-41080/CVE-2022-41082):-

2019

  • 15.2.1118.15 – 15.2.1118.7 <– strict match of all 4 numbers required
  • 15.2.986.30 – 15.2.986.5 <– strict match of all 4 numbers required
  • 15.2.922.27 – 15.2.196.0 (anything less than or equal to 15.2.922 )

^^^ looser match of the first 3 numbers is required

2016

  • 15.1.2507.13 – 15.1.2507.6 <– strict match of all 4 numbers required
  • 15.1.2375.32 – 15.1.2375.7 <– strict match of all 4 numbers required
  • 15.1.2308.27 – 15.1.225.16 (anything less than or equal to 15.1.2308)

^^^ looser match of the first 3 numbers is required

2013

  • 15.0.1497.31 – 15.0.1497.2 <– strict match of all 4 numbers required
  • 15.0.1473.6 – 15.0.516.32 (anything less than or equal to 15.0.1473)

^^^ looser match of the first 3 numbers is required

Attackers can use this vulnerability to escalate privileges on compromised servers, and they can also end up being able to execute arbitrary code remotely.

Recommendation

During the November 2022 Patch Tuesday, Microsoft released security updates that addressed the flaws in order to resolve them. During the month of September, GreyNoise, a company providing threat intelligence, has been closely monitoring the ongoing exploitation of ProxyNotShell.

As a security precaution, it is recommended that you apply the ProxyNotShell security patches from Microsoft released in November. This will ensure that your Exchange servers remain protected from incoming attacks.

A mitigation plan was also provided by the company, but attackers can circumvent those measures. In short, the only servers that are secure from compromise are those that are fully patched.

Gurubaran

Gurubaran is a co-founder of Cyber Security News and GBHackers On Security. He has 10+ years of experience as a Security Consultant, Editor, and Analyst in cybersecurity, technology, and communications.

Recent Posts

Attackers Exploit Microsoft Entra Billing Roles to Escalate Privileges in Organizational Environments

A startling discovery by BeyondTrust researchers has unveiled a critical vulnerability in Microsoft Entra ID…

17 hours ago

Threat Actors Exploit Google Apps Script to Host Phishing Sites

The Cofense Phishing Defense Center has uncovered a highly strategic phishing campaign that leverages Google…

18 hours ago

Dadsec Hacker Group Uses Tycoon2FA Infrastructure to Steal Office365 Credentials

Cybersecurity researchers from Trustwave’s Threat Intelligence Team have uncovered a large-scale phishing campaign orchestrated by…

19 hours ago

Beware: Weaponized AI Tool Installers Infect Devices with Ransomware

Cisco Talos has uncovered a series of malicious threats masquerading as legitimate AI tool installers,…

19 hours ago

Pure Crypter Uses Multiple Evasion Methods to Bypass Windows 11 24H2 Security Features

Pure Crypter, a well-known malware-as-a-service (MaaS) loader, has been recognized as a crucial tool for…

20 hours ago

Attackers Exploit Microsoft Entra Billing Roles to Escalate Privileges

A recent discovery by security researchers at BeyondTrust has revealed a critical, yet by-design, security…

20 hours ago