SIEM
Over the past two months researchers have reported three vulnerabilities that can be exploited to bypass authentication in Fortinet products using the FortiCloud SSO mechanism. The first two – CVE-2025-59718 and CVE-2025-59719 – were found by the company’s experts during a code audit (although CVE-2025-59718 has already made it into CISA’s Known Exploited Vulnerabilities Catalog), while the third – CVE-2026-24858 – was identified directly during an investigation of unauthorized activity on devices. These vulnerabilities allow attackers with a FortiCloud account to log into various companies’ FortiOS, FortiManager, FortiAnalyzer, FortiProxy, and FortiWeb accounts if the SSO feature is enabled on the given device.
To protect companies that use both our Kaspersky Unified Monitoring and Analysis Platform and Fortinet devices, we’ve created a set of correlation rules that help detect this malicious activity. The rules are already available for customers to download from Kaspersky SIEM repository; the package name is: [OOTB] FortiCloud SSO abuse package – ENG.
Contents of the FortiCloud SSO abuse package
The package includes three groups of rules. They’re used to monitor the following:
- Indicators of compromise: source IP addresses, usernames, creation of a new account with specific names;
- critical administrator actions, such as logging in from a new IP address, creating a new account, logging in via SSO, logging in from a public IP address, exporting device configuration;
- suspicious activity: configuration export or account creation immediately after a suspicious login.
Rules marked “(info)” may potentially generate false positives, as events critical for monitoring authentication bypass attempts may be entirely legitimate. To reduce false positives, add IP addresses or accounts associated with legitimate administrative activity to the exceptions.
As new attack reports emerge, we plan to supplement the rules marked with “IOC” with new information.
Additional recommendations
We also recommend using rules from the FortiCloud SSO abuse package for retrospective analysis or threat hunting. Recommended analysis period: starting from December 2025.
For the detection rules to work correctly, you need to ensure that events from Fortinet devices are received in full and normalized correctly. We also recommend configuring data in the “Extra” field when normalizing events, as this field contains additional information that may need investigating.
Learn more about our Kaspersky Unified Monitoring and Analysis Platform at on the official solution page.
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