This security bulletin contains one medium risk vulnerability.
CWE-200 - Information Exposure
Exploit availability: NoDescription
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a timing flaw in the TLS specification. A remote attacker can compute the pre-master secret in connections which have used a Diffie-Hellman (DH) based ciphersuite and eavesdrop on all encrypted communications sent over that TLS connection.
Note: The attack can only be exploited if an implementation re-uses a DH secret across multiple TLS connections.Mitigation
Install update from vendor's website.
Note, 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.Vulnerable software versions
Palo Alto PAN-OS: 8.1 - 8.1.20, 9.0 - 9.0.15, 9.1 - 9.1.11
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.