## November 23, 2003

### More MT Spam Vulnerabilities

I think we got us a theme going…

Remember insecure formmail scripts? How very 1990s, eh?

As if comment spam were not bad enough, MovableType includes, in its default installation, a CGI script called mt-send-entry.cgi which — you guessed it! — can be used to send email anonymously to anyone in the world.

And, no, this is not a merely theoretical issue; it’s being actively exploited by spammers.

Ben Trott has proposed the following patch to address the issue

--- mt-send-entry.cgi.orig      Sun Nov 23 20:21:12 2003
+++ mt-send-entry.cgi   Sun Nov 23 21:23:48 2003
@@ -37,6 +37,8 @@
die "Missing required parameters\n";
}

+    die "Invalid from or to value"
+       if $to =~ /[\r\n]/ ||$from =~ /[\r\n]/;
my $entry = MT::Entry->load($entry_id)
or die "Invalid entry ID '$entry_id'"; my$blog = MT::Blog->load(\$entry->blog_id);

But that addresses only one of the various ways in which this script can be exploited. Spammers can still send as much email as they want, with arbitrary message body content, to whomever they want, and do so completely anonymously. The only thing they can’t get rid of is the subject line

Subject: [Your Blog Name] Recommendation: Your Entry Title

which serves only to sully your reputation, and the first line of the message body,

Some fake email address has sent you a link!

(The link to your blog entry itself — at the bottom of the message body — is easily omitted, not that anyone will care.)

Unless you feel you absolutely must use this CGI script to allow anonymous visitors to mail arbitrary messages to whomever they please, you’d be much better off simply disabling it. Change the permissions on the offending script to make it inexecutable, or remove it entirely.

Do it now, before your blog is exploited by spammers.

Update (11/26/2003): Ben Trott has posted a message warning the vast majority of MT users, who don’t use this CGI script, to disable/remove it. He’s also posted an improved version (better than the patch above, but still only “spam-resistant”, rather than “spam-proof”) of the script.

Posted by distler at November 23, 2003 9:57 PM

TrackBack URL for this Entry:   http://golem.ph.utexas.edu/cgi-bin/MT-3.0/dxy-tb.fcgi/252

Read the post MT Spam Vulnerability
Excerpt: I just knew all thatsend this entry' crap was a bad idea
Tracked: November 25, 2003 10:16 PM
Weblog: minid.net
Excerpt: Movable Type 2.6 tiene un agujero de seguridad, la molestia ahora es un archivo llamado mt-send-entry.cgi.
Tracked: November 26, 2003 6:42 AM
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Tracked: November 26, 2003 7:48 AM
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Tracked: November 26, 2003 7:50 AM
Read the post Disable MovableType's Send Entry Script
Weblog: hatch.org
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Tracked: November 26, 2003 8:26 AM
Read the post Aviso para usuarios de Movable Type
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Tracked: November 26, 2003 9:16 AM
Read the post mt-send-entry must be stopped
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Tracked: November 26, 2003 10:14 AM
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Tracked: November 26, 2003 11:39 AM
Weblog: Snapping Links II (The Revenge)
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Tracked: November 26, 2003 3:07 PM
Read the post Blogspam II: MT as a relay
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Tracked: November 26, 2003 4:35 PM
Weblog: Phoenix's Cave
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Tracked: November 27, 2003 2:30 AM
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Excerpt:
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Tracked: January 5, 2004 1:41 AM

### Re: More MT Spam Vulnerabilities

We had many problems with formmail. Many servers get banned for sending a spam without their knowledge…

Posted by: Gry java on January 14, 2004 10:06 AM | Permalink | Reply to this

### Re: MT “Post Status” Vulnerabilities

In a similar vein, don’t assume that people can’t read your “Draft” posts. Once you save it, they can submit comments and forcibly publish the entries.

Posted by: Joe Grossberg on January 21, 2004 5:35 PM | Permalink | Reply to this

### Re: More MT Spam Vulnerabilities

I’m looking for a megaton of SPAM to go my way. Feel free to SPAM the following accounts:

curly@csat.binc.net
moe@csat.binc.et

curly@csat.binc.net
moe@csat.binc.net

Posted by: curly on January 27, 2008 3:17 PM | Permalink | Reply to this

### Re: More MT Spam Vulnerabilities

Hi! I know this is a pretty old post, but you seem so knowledgeable about spam vulnerabilities in MT that I thought I’d take a chance and ask you about an MT post of mine that seems permanently marked in google search with a spam title:

http://emdashes.com/2007/07/women-filmgoers-and-women-film.php

I’ve searched all the text and all the comments for spam, and can’t find any. How could a spam title (about pharmaceuticals–you’ll see what I mean if you google “emdashes david denby doomed”) have attached itself to my post title in search? How can I get rid of it? It’s very frustrating, since it was a popular post and people still occasionally search for it.

Thanks a lot, if you’re reading these!

Emily

Posted by: Emily on October 22, 2011 12:28 PM | Permalink | Reply to this

### Re: More MT Spam Vulnerabilities

For even more fun, google “site:emdashes.com viagra”.

Looks like a PHP hack, in which they’ve injected some PHP code (into your database? into an “image” file on your site?), which sends alternate, spammy, content to some User-Agents (search engines), but the regular content to others.

Good luck cleaning up your site.

Posted by: Jacques Distler on October 22, 2011 2:28 PM | Permalink | PGP Sig | Reply to this

### Re: More MT Spam Vulnerabilities

Thanks for looking at it! That is very strange. I’m not a programmer; do you have any more info about that kind of hack? I can google it too, of course.

In the meantime, I’ll look through the image files! I searched all the templates for spam too.

Maybe I’ll change all my users’ MT passwords too just for the heck of it.

Thanks again, and any suggestions are invaluable–I hate that these popular posts, or posts I’m proud of for one reason or another, are infected with this junk.

Posted by: Emily on October 23, 2011 12:46 AM | Permalink | Reply to this

### Re: More MT Spam Vulnerabilities

First of all, let me convince you that this is real.

1. Install the User-Agent Switcher extension for Firefox.
2. Switch your UserAgent String to the one for the Googlebot ( “Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)`” ).

Most likely, the attackers have inserted some hostile PHP code into your templates. The MT Administrative interface will let you see whether the stuff (entries, comments and templates) in your database have been modified. (Assuming that it, too, has not been compromised.)

That leaves you with the problem of cleaning up the mess, and plugging the hole that allowed them access in the first place.

If you’re not comfortable with such matters, you may need to hire someone. I suggest talking to you hosting provider (since it’s not necessarily your account that was compromised).

Posted by: Jacques Distler on October 23, 2011 11:35 AM | Permalink | PGP Sig | Reply to this

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