Inliniac

I just read about a new issue with WordPress here at SecurityFocus. It’s a potential credential stealing vulnerability, so I quickly created these ModSecurity 2 rules:

SecDefaultAction “log,deny,status:403,phase:2,t:lowercase,t:escapeSeqDecode”
SecRule REQUEST_FILENAME “/wp-login.php$” “chain,msg:’WORDPRESS wp-login.php redirect_to credentials stealing attempt’,severity:2,t:normalisePath”
SecRule ARGS_NAMES “^redirect_to$” “chain”
SecRule ARGS:redirect_to “(ht|f)tps?\://”

I can still login to my WordPress install, so it seems that the rule does no harm. Use at your own risk!

Update: I’ve created a Snort rule as well:

alert tcp $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:”WORDPRESS wp-login.php redirect_to credentials stealing attempt”; flow:to_server,established; uricontent:”/wp-login.php”; nocase; uricontent:”redirect_to”; pcre:”/redirect_to=(ht|f)tps?\:\//iU”; classtype:web-application-attack; sid:4000003; rev:1;)

Update 2: fixed the Snort rule, thanks to Shirkdog for pointing out that it had some broken pcre in it. The rule is now included in the BleedingThreats ruleset (check here), however that (slightly modified) rule doesn’t detect the attack for me.

Update 3: the Bleeding rule is now fixed. I’ve updated the above rule as well.

Update 4: updated the ModSecurity rule to prevent a possible evasion by prepending tab chars to the redirect url. Thanks to Ryan Barnett for pointing this out.

My ISP is one of the few here in the Netherlands that provides a IPv6 tunnel broker. I have played with it some during the last year or so, but now decided to get a little more serious with it. So I’ve decided to enable it for my blog. When opening up my site to IPv6 one thing that is important is security. I will describe the status of IPv6 support of my current setup:

Linux firewalling: IPtables supports IPv6 for quite some time, however it only very recently gained stateful packet filtering support. This hasn’t made it into Debian Sarge or even backports yet, so I’m just using stateless filtering now.

Vuurmuur: my own IPtables frontend has no support for IPv6 at all. I’ve been thinking about adding it for years, but decided to wait at least until stateful support would be available. Next to this my coding time is limited, and many other features are probably more interesting to Vuurmuur users.

Snort/Snort_inline: both Snort and Snort_inline lack support for IPv6. Sourcefire is working on it as far as I know, but no code is available from them. I did find a IPv6 patch for Snort 2.3.3, which can be found here. I ran it in sniffer mode and that works. I haven’t played with it much other than that, but I certainly will in the future.

ModSecurity: my Apache 2 installation has IPv6 enabled by default and ModSecurity 2.x just worked with it without any configuration change! I haven’t looked into how to create rules specific for IPv6 addresses however, so maybe surprises will come up here. I do know from looking at the source that the rbl functionality doesn’t support IPv6 addresses yet, but I haven’t even checked if realtime blacklists exist for IPv6.

Sguil/Modsec2sguil: my modsec2sguil script, that takes ModSecurity alerts and feeds them to Sguil, doesn’t act on the IPv6 alerts because it expects IPv4 addresses. This is not a problem however, since Sguil doesn’t support IPv6 addresses. This makes sense since Snort doesn’t support it either.

So compared to my IPv4 access, protection is somewhat limited. I’m only enabling HTTP for now, so ModSecurity should be able to handle that just fine.

Anyway, it seems to be working fine now, but consider the IPv6 support experimental, as I’m playing with how it all works. So don’t be surpised if it’s broken all of a sudden