Bug 1869468 (CVE-2020-8620)

Summary: CVE-2020-8620 bind: A specially crafted large TCP payload can trigger an assertion failure in tcpdns.c
Product: [Other] Security Response Reporter: Huzaifa S. Sidhpurwala <huzaifas>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: aegorenk, anon.amish, mruprich, msehnout, pemensik, pzhukov, security-response-team, thozza, vonsch, zdohnal
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: bind 9.16.6, bind 9.17.4 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-08-18 04:40:34 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1869469    

Description Huzaifa S. Sidhpurwala 2020-08-18 04:39:33 UTC 
As per upstream advisory:

In versions of BIND that use the libuv network manager (9.16.x is the only stable branch affected) an incorrectly specified maximum buffer size allows a specially crafted large TCP payload to trigger an assertion failure when it is received.

An attacker who can establish a TCP connection with the server and send data on that connection can exploit this to trigger the assertion failure, causing the server to exit.
Comment 1 Huzaifa S. Sidhpurwala 2020-08-18 04:39:37 UTC 
Acknowledgments:

Name: ISC
Upstream: Emanuel Almeida (Cisco Systems, Inc)
Comment 2 Huzaifa S. Sidhpurwala 2020-08-18 04:39:40 UTC 
Statement:

This version only affects bind-9.16.x. Therefore versions of bind package shipped with Red Hat Enterprise Linux are not affected by this flaw.
Comment 3 Huzaifa S. Sidhpurwala 2020-08-21 02:16:04 UTC 
External References:

https://kb.isc.org/docs/cve-2020-8620