Apache Update: TLS Certificate Authentication Bypass with HTTP/2 (CVE-2016-4979)
Apache released an important update today to fix a vulnerability that affects servers that have http/2 enabled and use TLS client certificates for authentication.
Apache 2.4.18-20 are vulnerable if:
- TLS certificates are used for authenticating clients (look for the "SSLVerifyClient require" directive in your configuration file)
- http/2 is enabled. (see if the "Protocols" line includes h2 and/or h2c).
Only access over http/2 is affected. Access via http/1.1 is still properly controlled even if http/2 is enabled. Over TLS, clients that suport http/2 will likely use it over http/1.1.
http/2 is not enabled by default in any currently shipping version of Apache.
To quickly check your network traffic for http/2 use, you can use this tshark line:
tshark -Y 'ssl.handshake.extensions_alpn_str == "h2"' -n -i en0 \
-T fields -e ip.src -e ip.dst -e ssl.handshake.type -e ssl.handshake.extensions_server_name \
-e ssl.handshake.extensions_alpn_str
It will list the client requests as well as the server responses that contain http/2 including the host name that the client is trying to reach. For example:
10.5.1.12 216.58.192.66 1 cm.g.doubleclick.net h2,spdy/3.1,http/1.1
216.58.192.66 10.5.1.12 2 h2
In this handshake, the client offers http/2, spdy/3.1 as well as http/1.1 to cm.g.doubleclick.net . The server then selects http/2 (h2).
Comments
www
Nov 17th 2022
6 months ago
EEW
Nov 17th 2022
6 months ago
qwq
Nov 17th 2022
6 months ago
mashood
Nov 17th 2022
6 months ago
isc.sans.edu
Nov 23rd 2022
6 months ago
isc.sans.edu
Nov 23rd 2022
6 months ago
isc.sans.edu
Dec 3rd 2022
5 months ago
isc.sans.edu
Dec 3rd 2022
5 months ago
<a hreaf="https://technolytical.com/">the social network</a> is described as follows because they respect your privacy and keep your data secure. The social networks are not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go.
<a hreaf="https://technolytical.com/">the social network</a> is not interested in collecting data about you. They don't care about what you're doing, or what you like. They don't want to know who you talk to, or where you go. The social networks only collect the minimum amount of information required for the service that they provide. Your personal information is kept private, and is never shared with other companies without your permission
isc.sans.edu
Dec 26th 2022
5 months ago
isc.sans.edu
Dec 26th 2022
5 months ago