# APT actors chain vulnerabilities against SLTT and elections infrastructure

Published: 2025-07-14 · Severity: high · Sectors: government-national, infrastructure
Canonical: https://vorant.io/reports/139fb885-ded6-5302-8e99-d34d9f5a0230/apt-actors-chain-vulnerabilities-against-sltt-and-elections-infrastructure

> APT groups exploit FortiOS VPN and Windows Netlogon flaws to compromise state and local government networks, including election support systems.

CISA and FBI report active exploitation of multiple vulnerabilities in a chaining attack targeting state, local, tribal, territorial (SLTT) government and critical infrastructure networks. APT actors begin with FortiOS SSL VPN CVE-2018-13379 or MobileIron CVE-2020-15505 to gain initial network access, then escalate privileges using the critical Windows Netlogon vulnerability CVE-2020-1472 to compromise Active Directory identity services. Once privileged, attackers maintain persistence using legitimate remote access tools (VPN, RDP) with stolen credentials. While unauthorized access to elections support systems has occurred, CISA reports no confirmed compromise of election data integrity.

The advisory identifies similar internet-facing vulnerabilities in other vendors (Citrix NetScaler CVE-2019-19781, Pulse Secure CVE-2019-11510, Palo Alto Networks CVE-2020-2021, F5 BIG-IP CVE-2020-5902, Juniper CVE-2020-1631) that could enable comparable attacks. The campaign affects multiple sectors beyond government. Defenders should assume breach, patch all external-facing infrastructure immediately, reset Active Directory credentials wholesale including the krbtgt account twice, and implement multi-factor authentication on VPN access.

## Mentioned in this report

- Vulnerabilities: CVE-2018-13379 (KEV), CVE-2019-11510 (KEV), CVE-2019-19781 (KEV), CVE-2020-1472 (KEV), CVE-2020-15505 (KEV), CVE-2020-1631 (KEV), CVE-2020-2021 (KEV), CVE-2020-5902 (KEV)

## Detection guidance (public sample)

### FortiOS SSL VPN Path Traversal Targeting Session File (CVE-2018-13379)

ATT&CK: T1190

Detects requests to the FortiOS SSL VPN fgt_lang endpoint with directory traversal or sslvpn_websession references, used to leak VPN credentials for initial access. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: FortiOS SSL VPN Path Traversal Targeting Session File (CVE-2018-13379)
description: Detects web requests to the FortiOS SSL VPN /remote/fgt_lang endpoint
  containing directory traversal sequences or references to the sslvpn_websession
  file. This is the exploitation pattern for CVE-2018-13379, used to read VPN session
  and credential data for initial access.
tags:
- attack.initial-access
- attack.t1190
- attack.t1133
logsource:
  category: webserver
detection:
  selection_path:
    cs-uri-stem|contains: /remote/fgt_lang
  selection_traversal:
    cs-uri-query|contains:
    - /../
    - sslvpn_websession
  condition: selection_path and selection_traversal
falsepositives:
- Authorized vulnerability scanners probing the VPN appliance
level: high
id: 45f37407-2f40-5f40-bcea-a0749ff4cb4b
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
```

### Zerologon Exploitation - Anonymous Logon Changing Computer Account Password

ATT&CK: T1078.002

Detects a computer account password change performed by ANONYMOUS LOGON, the Security log signature of Netlogon Zerologon (CVE-2020-1472) abuse that leads to domain compromise. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Zerologon Exploitation - Anonymous Logon Changing Computer Account Password
description: Detects Security event 4742 (computer account changed) where the subject
  is ANONYMOUS LOGON and the target is a computer account. This indicates Netlogon
  Zerologon (CVE-2020-1472) exploitation, which resets a domain controller machine
  account password and gives attackers privileged domain access. Run against domain
  controller logs.
tags:
- attack.privilege-escalation
- attack.t1078.002
- attack.t1078
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 4742
    SubjectUserName: ANONYMOUS LOGON
    TargetUserName|endswith: $
  condition: selection
falsepositives:
- Rare misconfigured legacy systems performing anonymous machine account updates
level: high
id: 2f3d921a-ff39-568a-83f2-59a2ec90c0b5
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
```

### Citrix or Pulse Secure Gateway Path Traversal Exploitation Attempt

ATT&CK: T1190

Detects directory traversal in request paths to Citrix /vpns/ or Pulse Secure /dana-na/ endpoints, matching exploitation of CVE-2019-19781 and CVE-2019-11510 against internet-facing VPN gateways. Auto-generated starting point — validate and tune in your environment before deploying. IOC matches can false-positive on shared infrastructure and decay as adversary infrastructure rotates.

```yaml
title: Citrix or Pulse Secure Gateway Path Traversal Exploitation Attempt
description: Detects directory traversal sequences in request paths to Citrix ADC/NetScaler
  /vpns/ or Pulse Secure /dana-na/ endpoints. These match exploitation of CVE-2019-19781
  and CVE-2019-11510, the same class of external-facing VPN gateway flaws used for
  initial access in chained attacks.
tags:
- attack.initial-access
- attack.t1190
- attack.t1133
logsource:
  category: webserver
detection:
  selection_citrix:
    cs-uri-stem|contains|all:
    - /vpns/
    - /../
  selection_pulse:
    cs-uri-stem|contains|all:
    - /dana-na/
    - /../
  condition: 1 of selection_*
falsepositives:
- Authorized vulnerability scanning of VPN gateways
level: high
id: 26de04fd-9b3f-5467-aea1-42f2c9a21702
status: experimental
author: Vorant
references:
- https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a
```

Behavioural rules are generated from public reporting — validate in your environment before deploying.

Source reporting: https://www.cisa.gov/news-events/cybersecurity-advisories/aa20-283a

---

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