Bug 1886041 (CVE-2020-25862)

Summary: CVE-2020-25862 wireshark: TCP dissector crash (wnpa-sec-2020-12)
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED WONTFIX QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: alekcejk, denis, huzaifas, lemenkov, mruprich, msehnout, peter, rvokal, sergey.avseyev
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: wireshark 3.2.7, wireshark 3.0.14 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2021-06-29 20:32:28 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: 1886042, 1886197    
Bug Blocks: 1886053    

Description Guilherme de Almeida Suckevicz 2020-10-07 14:22:45 UTC 
In Wireshark 3.2.0 to 3.2.6, 3.0.0 to 3.0.13, and 2.6.0 to 2.6.20, the TCP dissector could crash. This was addressed in epan/dissectors/packet-tcp.c by changing the handling of the invalid 0xFFFF checksum.

References:
https://www.wireshark.org/security/wnpa-sec-2020-12.html
https://gitlab.com/wireshark/wireshark/-/issues/16816

Upstream patch:
https://gitlab.com/wireshark/wireshark/-/commit/7f3fe6164a68b76d9988c4253b24d43f498f1753
Comment 1 Guilherme de Almeida Suckevicz 2020-10-07 14:23:04 UTC 
Created wireshark tracking bugs for this issue:

Affects: fedora-all [bug 1886042]
Comment 3 Todd Cullum 2020-10-07 21:20:28 UTC 
Statement:

Wireshark as shipped with Red Hat Linux 5, 6, and 7 is not affected by this flaw as the vulnerable code was introduced in a subsequent version of Wireshark.
Comment 4 Todd Cullum 2020-10-07 21:57:44 UTC 
Flaw summary:

TCP packets with checksum of 0xFFFF are invalid and trigger an assertion failure coming from hfinfo_number_value_format_display(). The patch marks the checksum as bad even when the packet is processed.