CVE-2021-34523: (Pwn2Own) Microsoft Exchange Server PowerShell Improper Authentication Remote Code Execution Vulnerability
First published: Tue Jul 13 2021(Updated: )
Microsoft Exchange Server contains an unspecified vulnerability that allows for privilege escalation.
Credit: secure@microsoft.com secure@microsoft.com secure@microsoft.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Microsoft Exchange | ||
| Microsoft Exchange Server 2016 | =19 | |
| Microsoft Exchange Server 2016 | =20 | |
| Microsoft Exchange Server 2013 | =23 | |
| Microsoft Exchange Server 2019 | =8 | |
| Microsoft Exchange Server 2019 | =9 | |
| Microsoft Exchange Server | =2013-cumulative_update_23 | |
| Microsoft Exchange Server | =2016-cumulative_update_19 | |
| Microsoft Exchange Server | =2016-cumulative_update_20 | |
| Microsoft Exchange Server | =2019-cumulative_update_8 | |
| Microsoft Exchange Server | =2019-cumulative_update_9 | |
| Microsoft Exchange Server | ||
| =2013-cumulative_update_23 | ||
| =2016-cumulative_update_19 | ||
| =2016-cumulative_update_20 | ||
| =2019-cumulative_update_8 | ||
| =2019-cumulative_update_9 |
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Reference Links
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-34523 (Advisory)
- https://www.zerodayinitiative.com/advisories/ZDI-21-822/
- http://packetstormsecurity.com/files/163895/Microsoft-Exchange-ProxyShell-Remote-Code-Execution.html
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34523
- https://www.bleepingcomputer.com/news/security/uk-govt-links-2021-electoral-commission-breach-to-exchange-server/
- https://nvd.nist.gov/vuln/detail/CVE-2021-34523
Frequently Asked Questions
What is CVE-2021-34523?
CVE-2021-34523 is a vulnerability that allows remote attackers to execute arbitrary code on affected installations of Microsoft Exchange Server.
How severe is CVE-2021-34523?
CVE-2021-34523 has a severity rating of 9.8, which is considered critical.
Which software is affected by CVE-2021-34523?
CVE-2021-34523 affects Microsoft Exchange Server 2013, Microsoft Exchange Server 2016, and Microsoft Exchange Server 2019.
How can I fix CVE-2021-34523?
To fix CVE-2021-34523, you should apply the corresponding security patches provided by Microsoft for your specific version of Exchange Server.
Where can I find more information about CVE-2021-34523?
You can find more information about CVE-2021-34523 on the official Microsoft Security Response Center website and the Zero Day Initiative website.
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