PT-2021-7952 · Suricata+2 · Suricata+2
Chang Zedd
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Published
2021-09-26
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Updated
2025-03-31
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CVE-2021-45098
CVSS v2.0
7.8
High
| Vector | AV:N/AC:L/Au:N/C:N/I:C/A:N |
Name of the Vulnerable Software and Affected Versions
Suricata versions prior to 6.0.4
Description
An issue in Suricata allows bypassing or evading any HTTP-based signature by faking an RST TCP packet with random TCP options of the
md5header from the client side. After the three-way handshake, it's possible to inject an RST ACK with a random TCP md5header option. Then, the client can send an HTTP GET request with a forbidden URL. The server will ignore the RST ACK and send the response HTTP packet for the client's request. These packets will not trigger a Suricata reject action. The vulnerability is related to insufficient checking of the hash function when processing MD5 and AO RST packets, which can allow a remote attacker to implement a TCP Reset attack.Recommendations
For Suricata versions prior to 6.0.4, update to version 6.0.4 or later to resolve the issue. As a temporary workaround, consider restricting the handling of RST TCP packets with random TCP options of the
md5header to minimize the risk of exploitation.Exploit
Fix
Improper Access Control
Use of a Broken Cryptographic Algorithm
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Related Identifiers
Affected Products
Alt Linux
Debian
Suricata