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                             CERT-Renater

                 Note d'Information No. 2021/VULN538
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DATE                : 15/10/2021

HARDWARE PLATFORM(S): /

OPERATING SYSTEM(S): PAN-OS versions 8.1, 9.0, 9.1.

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https://securityadvisories.paloaltonetworks.com/CVE-2020-1968
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TITLE: CVE-2020-1968 PAN-OS: Impact of the Raccoon Attack Vulnerability
CVE-2020-1968

Palo Alto Networks Security Advisories / CVE-2020-1968

CVE-2020-1968 PAN-OS: Impact of the Raccoon Attack Vulnerability
CVE-2020-1968


Severity                3.7 . LOW
Attack Vector           NETWORK
Attack Complexity       HIGH
Privileges Required     NONE
User Interaction        NONE
Scope                   UNCHANGED
Confidentiality Impact  LOW
Integrity Impact        NONE
Availability Impact     NONE
NVD JSON
Published               2021-10-13
Updated                 2021-10-13
Reference               PAN-154936
Discovered externally


Description

In versions of Palo Alto Networks PAN-OS software earlier than PAN-OS
10.0, the DHE cipher available for use in traffic decryption improperly
shares a cryptographic secret across multiple TLS connections, which
weakens its cryptographic strength. This is a prerequisite for
successful exploitation of the Raccoon attack (CVE-2020-1968), which
allows an attacker to eavesdrop on encrypted traffic over those TLS
connections.

Components that are known to be impacted by this vulnerability:

Web Interface

SSL Forward-Proxy

SSL Inbound Inspection

GlobalProtect Portal

GlobalProtect Gateway

GlobalProtect Clientless VPN

This issue impacts all versions of PAN-OS 8.1, all versions of PAN-OS
9.0, and all versions of PAN-OS 9.1. This issue does not impact any
version of PAN-OS 10.0 or any later PAN-OS versions.

Prisma Access customers that have Prisma Access 2.1 firewalls are
impacted by this issue.


Product Status

    Versions      Affected Unaffected
Prisma Access 2.2 None     >= 2.2
Prisma Access 2.1 all
PAN-OS 10.1       None     10.1.*
PAN-OS 10.0       None     10.0.*
PAN-OS 9.1        9.1.*
PAN-OS 9.0        9.0.*
PAN-OS 8.1        8.1.*

Required Configuration for Exposure

This issue is only applicable to PAN-OS firewalls configured to use SSL
Forward Proxy, SSL Inbound Inspection, GlobalProtect Portal,
GlobalProtect Gateway, or GlobalProtect Clientless VPN and where the
usage of the DHE key exchange is not disabled.


Severity: LOW

CVSSv3.1 Base Score: 3.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N)


Exploitation Status

Palo Alto Networks is not aware of any malicious exploitation of this
issue.


Weakness Type

CWE-203 Information Exposure Through Discrepancy

CWE-326 Inadequate Encryption Strength


Solution

Apply any of the workarounds to mitigate the risk of CVE-2020-1968.

This issue is fixed in PAN-OS 10.0.0 and all later PAN-OS versions.

This issue is fixed in Prisma Access 2.2 and all later Prisma Access
versions.


Workarounds and Mitigations

For all major versions of PAN-OS software earlier than PAN-OS 10.0 that
use SSL Forward Proxy or SSL Inbound Proxy:

You must disable the DHE key exchange from the web interface. You can
change this setting by selecting 'Objects > Decryption Profile > SSL
Protocol Settings' and then disable (deselect) the 'DHE' option.

For all PAN-OS 9.0 and PAN-OS 9.1 versions using web interface,
GlobalProtect Portal, GlobalProtect Gateway, or GlobalProtect Clientless
VPN, you can use the following CLI command to disable the DHE key
exchange:

"set shared ssl-tls-service-profile cert certificate <certificate-name>
protocol-settings keyxchg-algo-dhe no"

For PAN-OS 8.1.20 and later PAN-OS 8.1 versions using web interface,
GlobalProtect Portal, GlobalProtect Gateway, or GlobalProtect Clientless
VPN, you can use the same CLI command to disable the DHE key exchange:

"set shared ssl-tls-service-profile cert certificate <certificate-name>
protocol-settings keyxchg-algo-dhe no"

PAN-OS 10.0 and later PAN-OS versions are not impacted by this issue.


Timeline

2021-10-13 Initial publication
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(C) 2020 Palo Alto Networks, Inc. All rights reserved.


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