CVE-2021-23192: Input Validation
First published: Wed Nov 03 2021(Updated: )
A flaw was found in the way samba implemented DCE/RPC. If a client to a Samba server sent a very large DCE/RPC request, and chose to fragment it, an attacker could replace later fragments with their own data, bypassing the signature requirements.
Credit: secalert@redhat.com secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Samba Samba | >=4.10.0<4.13.14 | |
| Samba Samba | >=4.14.0<4.14.10 | |
| Samba Samba | >=4.15.0<4.15.2 | |
| redhat/samba | <0:4.14.5-7.el8_5 | 0:4.14.5-7.el8_5 |
| redhat/samba | <0:4.13.3-8.el8_4 | 0:4.13.3-8.el8_4 |
| redhat/samba | <0:4.14.5-204.el8 | 0:4.14.5-204.el8 |
| redhat/samba | <4.15.2 | 4.15.2 |
| redhat/samba | <4.14.10 | 4.14.10 |
| redhat/samba | <4.13.14 | 4.13.14 |
| ubuntu/samba | <2:4.13.14+dfsg-0ubuntu0.20.04.1 | 2:4.13.14+dfsg-0ubuntu0.20.04.1 |
| ubuntu/samba | <2:4.13.14+dfsg-0ubuntu0.21.04.1 | 2:4.13.14+dfsg-0ubuntu0.21.04.1 |
| ubuntu/samba | <2:4.13.14+dfsg-0ubuntu0.21.10.1 | 2:4.13.14+dfsg-0ubuntu0.21.10.1 |
| ubuntu/samba | <2:4.13.14+dfsg-0ubuntu1 | 2:4.13.14+dfsg-0ubuntu1 |
| ubuntu/samba | <4.13.14 | 4.13.14 |
| debian/samba | 2:4.9.5+dfsg-5+deb10u3 2:4.9.5+dfsg-5+deb10u5 2:4.13.13+dfsg-1~deb11u5 2:4.13.13+dfsg-1~deb11u6 2:4.17.12+dfsg-0+deb12u1 2:4.19.6+dfsg-1 2:4.19.6+dfsg-3 |
Remedy
Setting ~~~ dcesrv:max auth states=0 ~~~ in the smb.conf will provide some mitigation against this issue.
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Reference Links
- https://bugzilla.redhat.com/show_bug.cgi?id=2019666
- https://security.gentoo.org/glsa/202309-06
- https://ubuntu.com/security/CVE-2021-23192
- https://www.samba.org/samba/security/CVE-2021-23192.html
- https://www.cve.org/CVERecord?id=CVE-2021-23192 https://nvd.nist.gov/vuln/detail/CVE-2021-23192 https://www.samba.org/samba/security/CVE-2021-23192.html
- https://access.redhat.com/errata/RHSA-2021:5082
- https://access.redhat.com/errata/RHSA-2022:0008
- https://access.redhat.com/errata/RHSA-2021:4843
- https://access.redhat.com/security/cve/cve-2021-23192
- https://launchpad.net/bugs/cve/CVE-2021-23192
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2021715
- https://bugzilla.samba.org/show_bug.cgi?id=14875
- https://security-tracker.debian.org/tracker/CVE-2021-23192
- https://www.samba.org/samba/history/samba-4.13.14.html
- https://ubuntu.com/security/notices/USN-5142-1
- https://www.cve.org/CVERecord?id=CVE-2021-23192
- https://nvd.nist.gov/vuln/detail/CVE-2021-23192
Parent vulnerabilities
(Appears in the following advisories)
Frequently Asked Questions
What is CVE-2021-23192?
CVE-2021-23192 is a vulnerability found in the way Samba implemented DCE/RPC, allowing an attacker to bypass signature requirements.
What is the severity of CVE-2021-23192?
The severity of CVE-2021-23192 is high, with a severity value of 7.5.
Which software versions are affected by CVE-2021-23192?
Samba versions up to 4.15.2, 4.14.10, and 4.13.14 are affected by CVE-2021-23192.
How can an attacker exploit CVE-2021-23192?
An attacker can exploit CVE-2021-23192 by sending a large DCE/RPC request to a Samba server and replacing later fragments with their own data.
Where can I find more information about CVE-2021-23192?
You can find more information about CVE-2021-23192 on the Red Hat Bugzilla and Red Hat Security websites.
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