CVE-2021-34444: Windows DNS Server Denial of Service Vulnerability

Overview

Severity

Medium (CVSS 6.5)

CVSS Vector

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

Category

Denial of Service

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2021-Jul

Released

2021-07-13

EPSS Score

3.71% (percentile: 88.0%)

FAQ

If my server is not configured to be a DNS server, it is vulnerable? No, this vulnerability is only exploitable if the server is configured to be a DNS server.

Affected Products (16)

Windows

• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows Server, version 2004 (Server Core installation)
• Windows Server, version 20H2 (Server Core Installation)
• Windows Server 2016
• Windows Server 2016 (Server Core installation)
• Windows Server 2012
• Windows Server 2012 (Server Core installation)
• Windows Server 2012 R2
• Windows Server 2012 R2 (Server Core installation)

ESU

• Windows Server 2008 for 32-bit Systems Service Pack 2
• Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
• Windows Server 2008 for x64-based Systems Service Pack 2
• Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)
• Windows Server 2008 R2 for x64-based Systems Service Pack 1
• Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)

Security Updates (11)

• 5004244
• 5004237
• 5004238
• 5004305
• 5004299
• 5004289
• 5004307
• 5004294
• 5004302
• 5004298
• 5004285

Acknowledgments

<a href="https://twitter.com/guhe120">Yuki Chen</a>, Ting Yu from CERT Team of Legendsec at Qi'anxin Group, Zhiyi Zhang And Liubenjin from Codesafe Team of Legendsec at Qi'anxin Group

Revision History

• 2021-07-13: Information published.