Bug 1886041 (CVE-2020-25862) - CVE-2020-25862 wireshark: TCP dissector crash (wnpa-sec-2020-12)
Summary: CVE-2020-25862 wireshark: TCP dissector crash (wnpa-sec-2020-12)
Keywords:
Status: CLOSED WONTFIX
Alias: CVE-2020-25862
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1886042 1886197
Blocks: 1886053
TreeView+ depends on / blocked
 
Reported: 2020-10-07 14:22 UTC by Guilherme de Almeida Suckevicz
Modified: 2021-06-29 20:32 UTC (History)
9 users (show)

Fixed In Version: wireshark 3.2.7, wireshark 3.0.14
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Last Closed: 2021-06-29 20:32:28 UTC
Embargoed:

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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.
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