Cacti is an open source platform which provides a robust and extensible operational monitoring and fault management framework for users. In affected versions a command injection vulnerability allows an unauthenticated user to execute arbitrary code on a server running Cacti, if a specific data source was selected for any monitored device. The vulnerability resides in the `remote_agent.php` file. This file can be accessed without authentication. This function retrieves the IP address of the client via `get_client_addr` and resolves this IP address to the corresponding hostname via `gethostbyaddr`. After this, it is verified that an entry within the `poller` table exists, where the hostname corresponds to the resolved hostname. If such an entry was found, the function returns `true` and the client is authorized. This authorization can be bypassed due to the implementation of the `get_client_addr` function. The function is defined in the file `lib/functions.php` and checks serval `$_SERVER` variables to determine the IP address of the client. The variables beginning with `HTTP_` can be arbitrarily set by an attacker. Since there is a default entry in the `poller` table with the hostname of the server running Cacti, an attacker can bypass the authentication e.g. by providing the header `Forwarded-For: <TARGETIP>`. This way the function `get_client_addr` returns the IP address of the server running Cacti. The following call to `gethostbyaddr` will resolve this IP address to the hostname of the server, which will pass the `poller` hostname check because of the default entry. After the authorization of the `remote_agent.php` file is bypassed, an attacker can trigger different actions. One of these actions is called `polldata`. The called function `poll_for_data` retrieves a few request parameters and loads the corresponding `poller_item` entries from the database. If the `action` of a `poller_item` equals `POLLER_ACTION_SCRIPT_PHP`, the function `proc_open` is used to execute a PHP script. The attacker-controlled parameter `$poller_id` is retrieved via the function `get_nfilter_request_var`, which allows arbitrary strings. This variable is later inserted into the string passed to `proc_open`, which leads to a command injection vulnerability. By e.g. providing the `poller_id=;id` the `id` command is executed. In order to reach the vulnerable call, the attacker must provide a `host_id` and `local_data_id`, where the `action` of the corresponding `poller_item` is set to `POLLER_ACTION_SCRIPT_PHP`. Both of these ids (`host_id` and `local_data_id`) can easily be bruteforced. The only requirement is that a `poller_item` with an `POLLER_ACTION_SCRIPT_PHP` action exists. This is very likely on a productive instance because this action is added by some predefined templates like `Device - Uptime` or `Device - Polling Time`. This command injection vulnerability allows an unauthenticated user to execute arbitrary commands if a `poller_item` with the `action` type `POLLER_ACTION_SCRIPT_PHP` (`2`) is configured. The authorization bypass should be prevented by not allowing an attacker to make `get_client_addr` (file `lib/functions.php`) return an arbitrary IP address. This could be done by not honoring the `HTTP_...` `$_SERVER` variables. If these should be kept for compatibility reasons it should at least be prevented to fake the IP address of the server running Cacti. This vulnerability has been addressed in both the 1.2.x and 1.3.x release branches with `1.2.23` being the first release containing the patch.

Cacti before 1.2.18 allows remote attackers to trigger XSS via template import for the midwinter theme.

In Cacti before 1.2.11, auth_profile.php?action=edit allows CSRF for an admin email change.

In Cacti before 1.2.11, disabling a user account does not immediately invalidate any permissions granted to that account (e.g., permission to view logs).

Cacti through 1.2.7 is affected by a graphs.php?template_id= SQL injection vulnerability affecting how template identifiers are handled when a string and id composite value are used to identify the template type and id. An authenticated attacker can exploit this to extract data from the database, or an unauthenticated remote attacker could exploit this via Cross-Site Request Forgery.

Cacti 1.2.8 has stored XSS in data_sources.php, color_templates_item.php, graphs.php, graph_items.php, lib/api_automation.php, user_admin.php, and user_group_admin.php, as demonstrated by the description parameter in data_sources.php (a raw string from the database that is displayed by $header to trigger the XSS).

Cacti through 1.2.7 is affected by multiple instances of lib/functions.php unsafe deserialization of user-controlled data to populate arrays. An authenticated attacker could use this to influence object data values and control actions taken by Cacti or potentially cause memory corruption in the PHP module.

In Cacti through 1.2.6, authenticated users may bypass authorization checks (for viewing a graph) via a direct graph_json.php request with a modified local_graph_id parameter.

In clearFilter() in utilities.php in Cacti before 1.2.3, no escaping occurs before printing out the value of the SNMP community string (SNMP Options) in the View poller cache, leading to XSS.

A cross-site scripting (XSS) vulnerability exists in host.php (via tree.php) in Cacti before 1.2.0 due to lack of escaping of unintended characters in the Website Hostname field for Devices.

A cross-site scripting (XSS) vulnerability exists in graph_templates.php in Cacti before 1.2.0 due to lack of escaping of unintended characters in the Graph Vertical Label.

A cross-site scripting (XSS) vulnerability exists in pollers.php in Cacti before 1.2.0 due to lack of escaping of unintended characters in the Website Hostname for Data Collectors.

A cross-site scripting (XSS) vulnerability exists in color_templates.php in Cacti before 1.2.0 due to lack of escaping of unintended characters in the Name field for a Color.

Cacti before 1.1.37 has XSS because it makes certain htmlspecialchars calls without the ENT_QUOTES flag (these calls occur when the html_escape function in lib/html.php is not used).

Cacti before 1.1.37 has XSS because it does not properly reject unintended characters, related to use of the sanitize_uri function in lib/functions.php.

Cacti before 1.1.37 has XSS because the get_current_page function in lib/functions.php relies on $_SERVER['PHP_SELF'] instead of $_SERVER['SCRIPT_NAME'] to determine a page name.

auth_login.php in Cacti before 1.0.0 allows remote authenticated users who use web authentication to bypass intended access restrictions by logging in as a user not in the cacti database, because the guest user is not considered. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-2313.

Cacti before 1.0.0 allows remote authenticated users to conduct PHP object injection attacks and execute arbitrary PHP code via a crafted serialized object, related to calling unserialize(stripslashes()).

lib/html.php in Cacti before 1.1.18 has XSS via the title field of an external link added by an authenticated user.

Cross-site scripting (XSS) vulnerability in aggregate_graphs.php in Cacti before 1.1.16 allows remote authenticated users to inject arbitrary web script or HTML via specially crafted HTTP Referer headers, related to the $cancel_url variable. NOTE: this vulnerability exists because of an incomplete fix (lack of the htmlspecialchars ENT_QUOTES flag) for CVE-2017-11163.