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             AUSCERT External Security Bulletin Redistribution

                               ESB-2022.5504
            AV Engine - evasion by manipulating MIME attachment
                              2 November 2022

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           AV Engine
                   FortiMail
                   FortiOS
Publisher:         Fortinet
Operating System:  Network Appliance
Resolution:        Patch/Upgrade
CVE Names:         CVE-2022-26122  

Original Bulletin: 
   https://fortiguard.fortinet.com/psirt/FG-IR-22-074

Comment: CVSS (Max):  4.3 CVE-2022-26122 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N)
         CVSS Source: Fortinet
         Calculator:  https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N

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AV Engine - evasion by manipulating MIME attachment

IR Number    : FG-IR-22-074
Date         : Nov 1, 2022
Severity     : Medium
CVSSv3 Score : 4.3
Impact       : Denial of service
CVE ID       : CVE-2022-26122
Affected Products: 

AV Engine:
6.33, 6.253, 6.252, 6.243, 6.157, 6.156, 6.145, 6.144, 6.142, 6.137, 4.4.54,
2.0.60, 2.0.49, 0.4.23


FortiMail:
7.0.2, 7.0.1, 7.0.0, 6.4.6, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.1, 6.4.0, 6.2.9, 
6.2.8, 6.2.7, 6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.1, 6.2.0, 6.0.9, 6.0.8, 
6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.12, 6.0.11, 6.0.10, 6.0.1, 6.0.0


FortiOS:
7.2.0, 7.0.6, 7.0.5, 7.0.4, 7.0.3, 7.0.2, 7.0.1, 7.0.0, 6.4.9, 6.4.8, 6.4.7, 
6.4.6, 6.4.5, 6.4.4, 6.4.3, 6.4.2, 6.4.10, 6.4.1, 6.4.0, 6.2.9, 6.2.8, 6.2.7, 
6.2.6, 6.2.5, 6.2.4, 6.2.3, 6.2.2, 6.2.11, 6.2.10, 6.2.1, 6.2.0, 6.0.9, 6.0.8, 
6.0.7, 6.0.6, 6.0.5, 6.0.4, 6.0.3, 6.0.2, 6.0.15, 6.0.14, 6.0.13, 6.0.12, 6.0.11, 
6.0.10, 6.0.1, 6.0.0

Summary

An insufficient verification of data authenticity vulnerability [CWE-345] in
FortiClient, FortiMail and FortiOS AV engines may allow
an attacker to bypass the AV engine via manipulating MIME attachment with junk
and pad characters in base64.

Affected Products

FortiOS running AV engine version 6.2.168 and below.
FortiOS running AV engine version 6.4.274 and below.
FortiMail running AV engine version 6.2.168 and below.
FortiMail running AV engine version 6.4.274 and below.
FortiClient running AV engine version 6.2.168 and below.
FortiClient running AV engine version 6.4.274 and below.

Solutions

Please upgrade AV engine to version 6.2.169 or above.
Please upgrade AV engine to version 6.4.275 or above.
Please upgrade to FortiMail version 7.2.0 or above
Please upgrade to FortiMail version 7.0.3 or above
Please upgrade to FortiMail version 6.4.7 or above
Please upgrade to FortiOS version 7.0.8 or above.
Please upgrade to FortiOS version 7.2.2 or above.

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