Security News > 2021 > November > Exploit released for Microsoft Exchange RCE bug, patch now
Proof-of-concept exploit code has been released online over the weekend for an actively exploited high severity vulnerability impacting Microsoft Exchange servers.
The security bug tracked as CVE-2021-42321 impacts on-premises Exchange Server 2016 and Exchange Server 2019 and was patched by Microsoft during this month's Patch Tuesday.
On Sunday, almost two weeks after the CVE-2021-42321 patch was issued, researcher Janggggg published a proof-of-concept exploit for the Exchange post-auth RCE bug.
"Our recommendation is to install these updates immediately to protect your environment," the company said, urging Exchange admins to patch the bug exploited in the wild.
If you haven't yet patched this security vulnerability in your on-premises servers, you can generate a quick inventory of all Exchange servers in your environment that need updating using the latest version of the Exchange Server Health Checker script.
In August, threat actors also began scanning for and breaching Exchange servers by exploiting ProxyShell vulnerabilities after security researchers reproduced a working exploit.
News URL
Related news
- Microsoft SharePoint RCE flaw exploits in the wild – you've had 3 months to patch (source)
- Exploit code released for critical Ivanti RCE flaw, patch now (source)
- Microsoft September 2024 Patch Tuesday fixes 4 zero-days, 79 flaws (source)
- Patch Tuesday for September 2024: Microsoft Catches Four Zero-Day Vulnerabilities (source)
- Week in review: Veeam Backup & Replication RCE could soon be exploited, Microsoft fixes 4 0-days (source)
- Microsoft confirms IE bug squashed in Patch Tuesday was exploited zero-day (source)
- SolarWinds Issues Patch for Critical ARM Vulnerability Enabling RCE Attacks (source)
- 'Patch yesterday': Zimbra mail servers under siege through RCE vuln (source)
- Critical Ivanti RCE flaw with public exploit now used in attacks (source)
- Week in review: Critical Zimbra RCE vulnerability exploited, Patch Tuesday forecast (source)
Related Vulnerability
DATE | CVE | VULNERABILITY TITLE | RISK |
---|---|---|---|
2021-11-10 | CVE-2021-42321 | Unspecified vulnerability in Microsoft Exchange Server 2016/2019 Microsoft Exchange Server Remote Code Execution Vulnerability | 8.8 |