CVE-2020-2035

Summary

CVECVE-2020-2035
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2020-08-12 17:15:00 UTC
Updated2021-10-19 13:23:00 UTC
DescriptionWhen SSL/TLS Forward Proxy Decryption mode has been configured to decrypt the web transactions, the PAN-OS URL filtering feature inspects the HTTP Host and URL path headers for policy enforcement on the decrypted HTTPS web transactions but does not consider Server Name Indication (SNI) field within the TLS Client Hello handshake. This allows a compromised host in a protected network to evade any security policy that uses URL filtering on a firewall configured with SSL Decryption in the Forward Proxy mode. A malicious actor can then use this technique to evade detection of communication on the TLS handshake phase between a compromised host and a remote malicious server. This technique does not increase the risk of a host being compromised in the network. It does not impact the confidentiality or availability of a firewall. This is considered to have a low impact on the integrity of the firewall because the firewall fails to enforce a policy on certain traffic that should have been blocked. This issue does not impact the URL filtering policy enforcement on clear text or encrypted web transactions. This technique can be used only after a malicious actor has compromised a host in the protected network and the TLS/SSL Decryption feature is enabled for the traffic that the attacker controls. Palo Alto Networks is not aware of any malware that uses this technique to exfiltrate data. This issue is applicable to all current versions of PAN-OS. This issue does not impact Panorama or WF-500 appliances.

Risk And Classification

Problem Types: NVD-CWE-noinfo

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Paloaltonetworks Pan-os All All All All
Operating System Paloaltonetworks Pan-os All All All All

References

ReferenceSourceLinkTags
CVE-2020-2035 PAN-OS: URL filtering policy is not enforced on TLS handshakes for decrypted HTTPS sessions CONFIRM security.paloaltonetworks.com Vendor Advisory
SNIcat: Circumventing the guardians | mnemonic CONFIRM www.mnemonic.no Third Party Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

LEGACY: Palo Alto Networks thanks Morten Marstrander and Matteo Malvica from mnemonic AS for discovering and reporting this issue.

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