FBI says an APT breached a US municipal government via an unpatched Fortinet VPN
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 article323 words · extracted from therecord.media · click to collapse
The Federal Bureau of Investigation said today that foreign hackers had breached the network of a local US municipal government after exploiting vulnerabilities in an unpatched Fortinet networking appliance. The intrusion was detected this month, in May 2021, the FBI said in an industry alert [PDF] published on one of its websites. The hack comes after the FBI had previously warned the US private sector and government agencies to patch Fortinet devices a month earlier, in April 2021. At the time, the FBI said that foreign nation-state hacking groups—also known as Advanced Persistent Threats (APTs)—were scanning the internet for Fortinet devices vulnerable to three bugs tracked as CVE 2018-13379, CVE-2020-12812, and CVE-2019-5591. But despite the early alert, hackers appear to have been successful in breaching at least one organization. As of at least May 2021, an APT actor group almost certainly exploited a Fortigate appliance to access a webserver hosting the domain for a U.S. municipal government. The FBI said that in this particular intrusion, the attacker created a backdoor account named "elie," which they used to pivot from the compromised Fortinet VPN appliance to the victim's internal network. Once the threat actor gained access to the victim's internal network, they usually created further backdoor accounts for future access on systems like domain controllers, servers, workstations, and active directories. Some of these accounts appear to have been created to look similar to other existing accounts on the network, so specific account names may vary per organization. In addition to unrecognized user accounts or accounts established to masquerade as existing accounts, the following account usernames may be associated with this activity FBI Flash Alert MI-000148-MW The FBI is now urging organizations—once again—to patch their Fortinet devices. By giving an example of a compromised entity, officials hope that organizations will take their current and previous warnings more seriously than before.
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