Уязвимость функции addRelatedObjects универсальной системы мониторинга Zabbix, позволяющая нарушителю повысить свои привилегии

When a URL is added to the map element, it is recorded in the database with sequential IDs. Upon adding a new URL, the system retrieves the last sysmapelementurlid value and increments it by one. However, an issue arises when a user manually changes the sysmapelementurlid value by adding sysmapelementurlid + 1. This action prevents others from adding URLs to the map element.

The implementation of atob in "Zabbix JS" allows to create a string with arbitrary content and use it to access internal properties of objects.

A bug in the code allows an attacker to sign a forged zbx_session cookie, which then allows them to sign in with admin permissions.

An authenticated user with API access (e.g.: user with default User role), more specifically a user with access to the user.update API endpoint is enough to be able to add themselves to any group (e.g.: Zabbix Administrators), except to groups that are disabled or having restricted GUI access.

The reported vulnerability is a stack buffer overflow in the zbx_snmp_cache_handle_engineid function within the Zabbix server/proxy code. This issue occurs when copying data from session->securityEngineID to local_record.engineid without proper bounds checking.

There was discovered a use after free bug in browser.c in the es_browser_get_variant function

A non-admin user account on the Zabbix frontend with the default User role, or with any other role that gives API access can exploit this vulnerability. An SQLi exists in the CUser class in the addRelatedObjects function, this function is being called from the CUser.get function which is available for every user who has API access.

When the webdriver for the Browser object downloads data from a HTTP server, the data pointer is set to NULL and is allocated only in curl_write_cb when receiving data. If the server's response is an empty document, then wd->data in the code below will remain NULL and an attempt to read from it will result in a crash.

The webdriver for the Browser object expects an error object to be initialized when the webdriver_session_query function fails. But this function can fail for various reasons without an error description and then the wd->error will be NULL and trying to read from it will result in a crash.

The HttpRequest object allows to get the HTTP headers from the server's response after sending the request. The problem is that the returned strings are created directly from the data returned by the server and are not correctly encoded for JavaScript. This allows to create internal strings that can be used to access hidden properties of objects.

In the src/libs/zbxembed/browser.c file, the es_browser_ctor method retrieves a heap pointer from the Duktape JavaScript engine. This heap pointer is subsequently utilized by the browser_push_error method in the src/libs/zbxembed/browser_error.c file. A use-after-free bug can occur at this stage if the wd->browser heap pointer is freed by garbage collection.

The researcher is showing that due to the way the SNMP trap log is parsed, an attacker can craft an SNMP trap with additional lines of information and have forged data show in the Zabbix UI. This attack requires SNMP auth to be off and/or the attacker to know the community/auth details. The attack requires an SNMP item to be configured as text on the target host.

The researcher is showing that it is possible to leak a small amount of Zabbix Server memory using an out of bounds read in src/libs/zbxmedia/email.c