CISA: Patch These Three Fortinet Bugs Now to Avoid Compromise
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2019-5591 | Default-Configuration LDAP Impersonation in Fortinet FortiOS CVE-2019-5591 is a default-configuration flaw in Fortinet FortiOS (CWE-306, missing authentication for a critical function): when a FortiGate acts as an LDAP client over SSL/TLS for authentication purposes, the default configuration does not properly authenticate the LDAP server, allowing an unauthenticated attacker on the same subnet to impersonate the LDAP server. The attack requires adjacency (the attacker must be on the same network segment as the device's LDAP traffic) and only works where the device uses LDAP over TLS with the default, non-validating settings. A successful attacker can intercept sensitive authentication information, such as usernames and passwords, exchanged with the LDAP server, with high confidentiality impact but no integrity or availability impact per the CVSS score. Organizations running affected FortiOS releases with LDAP-over-TLS configured are exposed; FortiOS runs on one of the largest firewall/VPN installed bases, though the source data does not state exact affected version ranges or deployment counts. The flaw is listed in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) with known in-the-wild and ransomware use; late-2021 CISA and FBI advisories warned that APT actors were exploiting Fortinet bugs, including this one, for initial access, and no public PoC is known. Do: Upgrade affected FortiGate/FortiOS units to a fixed release (6.2.1+, 6.0.8+, 5.6.10+, or 5.4.12+) per Fortinet's instructions, as required by CISA's KEV listing. If patching is delayed, disable the use of SSL/TLS in the LDAP server configuration or restrict and monitor the network path between the FortiGate and the LDAP server. Inventory which devices use LDAPS for authentication and review authentication logs for signs of server impersonation or credential theft. | 6.5 | 18% | KEV ransomware |
| largetens of thousands of FortiGate deployments plausibly affected (a subset of a very large FortiOS installed base that connects to LDAP over TLS) | |
| CVE-2020-12812 | MFA Bypass via Username Case Change in Fortinet FortiOS SSL VPN Fortinet FortiOS SSL VPN improperly validates the second factor of authentication (FortiToken), allowing a user with valid primary credentials to log in without being prompted for their one-time token. The bypass is triggered by changing the letter case of the username (e.g., typing 'Admin' instead of 'admin'), a case-sensitivity handling flaw (CWE-178) in the authentication logic (CWE-287). An attacker who has stolen, phished, or reused a user's primary credentials can therefore gain full SSL VPN access without the multi-factor protection defenders assume is enforced. Any organization running an affected FortiOS SSL VPN portal with FortiToken two-factor authentication for users is exposed. The flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) with known ransomware use, and EPSS assigns a 49.3% probability of exploitation within 30 days (99th percentile); no public PoC is known. Do: Apply the FortiOS update per Fortinet's advisory, as required by CISA's KEV listing. Until patched, audit SSL VPN logs for successful logins in which no FortiToken second-factor prompt occurred (especially sessions authenticating with altered username case), and consider restricting the SSL VPN portal to trusted source addresses or disabling it temporarily. Any accounts found with second-factor-free VPN logins should have credentials rotated and be checked for follow-on compromise, given known ransomware use. | 9.8 | 49% | KEV ransomware |
| masson the order of hundreds of thousands of internet-exposed FortiOS SSL VPN portals (public scans in 2020-2021 counted roughly 150,000-500,000) |
Full article306 words · extracted from infosecurity-magazine.com · click to collapse
The US authorities are urging Fortinet customers to patch three legacy vulnerabilities being exploited in the wild to compromise government, commercial and technology service provider networks.
A joint cybersecurity advisory from the FBI and the Cybersecurity and Infrastructure Security Agency (CISA) on Friday warned that threat actors are actively scanning for devices via ports 4443, 8443 and 10443, with the potential end goals of data theft or ransomware deployment.
“The FBI and CISA believe the APT actors are likely exploiting these Fortinet FortiOS vulnerabilities — CVE 2018-13379, CVE-2020-12812, and CVE-2019-5591 — to gain access to multiple government, commercial and technology services networks,” it said.
“The APT actors may be using any or all of these CVEs to gain access to networks across multiple critical infrastructure sectors, to gain access to key networks as pre-positioning for follow-on data exfiltration or data encryption attacks. APT actors may use other CVEs or common exploitation techniques — such as spear-phishing — to gain access to critical infrastructure networks to pre-position for follow-on attack.”
Patches for the first two vulnerabilities have been available since May and July 2019, while the third was fixed by Fortinet in July last year.
CVE 2018-13379 is a patch traversal flaw which allows unauthenticated attackers to download system files, while CVE-2020-12812 is an improper authentication vulnerability in SSL VPN which allows users to log-in without being prompted for a second factor if they change their username case. Both have a CVSS score of 9.8, meaning they’re classed as “critical.”
CVE-2019-5591 is a default configuration vulnerability in FortiOS which could allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server. It has a score of 7.5, making it a high severity bug.
Fortinet said it had repeatedly urged customers to patch the offending vulnerabilities over the past couple of years.
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.infosecurity-magazine.com/news/patch-fortinet-bugs-now-avoid/