Concrete5 versions 8.5.5 suffer from a logging settings phar deserialization vulnerability. User input passed through the logFile request parameter is not properly sanitized before being used in a call to the file_exists() function at line 91. This can be exploited by malicious users to inject arbitrary PHP objects into the application scope (PHP Object Injection via phar:// stream wrapper), allowing them to carry out a variety of attacks, such as executing arbitrary PHP code. Successful exploitation of this vulnerability requires an administrator account.
a1fb25a9ba4326669a0ede911fe27d02------------------------------------------------------------------------
Concrete5 <= 8.5.5 (Logging Settings) Phar Deserialization Vulnerability
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[-] Software Link:
https://www.concrete5.org
[-] Affected Versions:
Version 8.5.5 and prior versions.
[-] Vulnerability Description:
The vulnerable code is located within the
/concrete/controllers/single_page/dashboard/system/environment/logging.php
script. Specifically, into the Logging::update_logging() method:
61. public function update_logging()
62. {
63. $config = $this->app->make('config');
64. $request = $this->request;
65.
66. if (!$this->token->validate('update_logging')) {
67. return
$this->showError($this->token->getErrorMessage());
68. }
69.
70. // Load in variables from the request
71. $mode = (string) $request->request->get('logging_mode') ===
'advanced' ? 'advanced' : 'simple';
72. $handler = $mode === 'simple' ? (string)
$request->request->get('handler', 'database') : null;
73. $logFile = $handler === 'file' ? (string)
$request->request->get('logFile') : null;
74. $enableDashboardReport =
$request->request->get('enable_dashboard_report') ? true : false;
75. $loggingLevel = strtoupper((string)
$request->request->get('logging_level'));
76. $intLogErrorsPost =
$request->request->get('ENABLE_LOG_ERRORS') === 1 ? 1 : 0;
77. $intLogEmailsPost =
$request->request->get('ENABLE_LOG_EMAILS') === 1 ? 1 : 0;
78. $intLogApiPost = $request->request->get('ENABLE_LOG_API')
=== 1 ? 1 : 0;
79.
80.
81. // Handle 'file' based logging
82. if ($handler === 'file') {
83. $directory = dirname($logFile);
84.
85. // Validate the file name
86. if (pathinfo($logFile, PATHINFO_EXTENSION) !== 'log') {
87. return $this->showError(t('The filename provided
must be a valid filename and end with .log'));
88. }
89.
90. // Validate the file path, create the log file if needed
91. if (!file_exists($logFile)) {
User input passed through the "logFile" request parameter is not
properly sanitized before being used in a call to the file_exists()
function at line 91. This can be exploited by malicious users to inject
arbitrary PHP objects into the application scope (PHP Object Injection
via phar:// stream wrapper), allowing them to carry out a variety of
attacks, such as executing arbitrary PHP code. Successful exploitation
of this vulnerability requires an administrator account.
[-] Solution:
No official solution is currently available.
[-] Disclosure Timeline:
[20/12/2020] - Vendor notified through HackerOne
[22/12/2020] - Vendor asks suggestions to fix the issue, feedback
provided
[18/03/2021] - Version 8.5.5 released, vulnerability not fixed
[02/06/2021] - Asked for an update, no response
[06/07/2021] - Asked for an update, no response
[16/07/2021] - CVE number assigned
[19/07/2021] - Public disclosure
[-] CVE Reference:
The Common Vulnerabilities and Exposures project (cve.mitre.org)
has assigned the name CVE-2021-36766 to this vulnerability.
[-] Credits:
Vulnerability discovered by Egidio Romano.
[-] Other References:
https://hackerone.com/reports/1063039
[-] Original Advisory:
http://karmainsecurity.com/KIS-2021-05