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Thai Broadband Provider Hacked via Fortinet Vulnerability

AI summary · glm-5.3

Hackers exploited Fortinet CVE-2024-21762 RCE to breach Thai broadband provider 3BB, deploying MeshCentral backdoors and credential-harvesting tools across its network.

Hunt.io uncovered an intrusion staging directory in Thailand containing 298 files of custom tooling built for Triple T Broadband (3BB) and its former owner Jasmine. Initial access came via fingerprinting a FortiGate SSL-VPN appliance and exploiting CVE-2024-21762 for remote code execution, after probing CVE-2018-13379, CVE-2022-42475, and CVE-2023-27997. The actor also probed F5 BIG-IP for CVE-2021-22986, CVE-2022-1388, and CVE-2023-46747, escalated privileges with PwnKit and Dirty COW, used MeshCentral as a C2 backdoor, harvested SSH/database/SNMP/Radius credentials, deployed PHP web shells, and ran cleanup scripts to hide the intrusion.

  • 298-file staging directory exposed attacker toolkit custom-built for 3BB and Jasmine
  • Initial access via FortiGate SSL-VPN fingerprinting and CVE-2024-21762 RCE exploit
  • PwnKit and Dirty COW used for Linux privilege escalation with SUID backdoor
  • MeshCentral configured as persistent C2; credential harvesting drove lateral movement
  • Cleanup script removed artifacts while verifying SUID backdoor and MeshCentral persistence

Vulnerabilities mentionedAll →

CVEVulnerabilityCVSSEPSSFlagsAffectedExposurePublished
CVE-2018-13379
Unauthenticated Path Traversal in Fortinet FortiOS SSL VPN

CVE-2018-13379 is a path traversal flaw (CWE-22) in the Fortinet FortiOS SSL VPN web portal that allows an unauthenticated attacker to download FortiOS system files via specially crafted HTTP resource requests. By traversing directories through crafted requests to the exposed web portal, the attacker can retrieve sensitive files, a technique publicly documented as yielding the SSL VPN session file containing usernames and passwords in plaintext. Any organization running the SSL VPN web portal on a FortiGate appliance is affected, and risk is highest where the portal is directly reachable from the internet. The flaw is confirmed in the wild: it was added to the CISA KEV catalog on 2021-11-03 with known ransomware use, and EPSS assigns it a 100% probability of exploitation within 30 days. No public PoC is listed in the provided data, but credential theft tied to this bug has been widely reused by threat actors.

Do: Apply the patched FortiOS release per Fortinet's vendor advisory immediately, as this is a CISA KEV required action; if the fixed version is not known from this data, follow Fortinet's FG-IR-18-384 advisory for the correct upgrade path. Rotate SSL VPN credentials and review VPN access logs for path-traversal requests, since successful exploitation exposes plaintext session credentials, and restrict SSL VPN portal exposure to trusted sources where possible.

9.8100% KEV ransomware
  • Fortinet FortiOS
mass≈500,000 internet-exposed FortiOS SSL VPN portals (Fortinet cited ~480,000 affected devices)
CVE-2021-22986
Unauthenticated RCE in F5 BIG-IP and BIG-IQ iControl REST

F5 BIG-IP and BIG-IQ Centralized Management contain a remote code execution vulnerability (CWE-863, improper authorization check) in the iControl REST interface. An unauthenticated attacker with network access to the REST endpoint can send crafted requests to execute arbitrary system commands, create or delete files, and disable services on the appliance or virtual instance. Successful exploitation effectively gives the attacker command-level control of the underlying F5 system, which is sufficient for account creation, persistence, lateral movement, and ransomware staging. Any organization running affected BIG-IP or BIG-IQ releases is exposed, particularly where the management interface or iControl REST is reachable from untrusted networks. Exploitation is confirmed in the wild: the flaw was added to CISA's KEV on 2021-11-03 with known ransomware use, EPSS places the 30-day exploitation probability at 99.9% (top percentile), though no public PoC is cataloged.

Do: Upgrade BIG-IP and BIG-IQ to the fixed releases identified in F5's advisory (K03051234) on an urgent basis, since exploitation is in the wild and ransomware actors use this flaw. Until patched, restrict network access to the management interface and iControl REST to trusted administration networks. Because ransomware use is known, review affected devices for indicators of compromise such as unexpected commands, created or deleted files, and disabled services.

9.8100% KEV ransomware PoC ×2
  • F5 BIG-IP
  • F5 BIG-IQ Centralized Management
largetens of thousands of internet-exposed BIG-IP management interfaces (public scan counts at disclosure), within a total installed base of hundreds of thousands…
CVE-2022-1388
Unauthenticated RCE in F5 BIG-IP via Missing Authentication

F5 BIG-IP contains a critical missing-authentication flaw (CWE-306) in its iControl REST control plane: an unauthenticated attacker with network reachability to the management interface, or to self IPs exposing the REST service on TCP 443, can bypass authentication completely. By sending specially crafted HTTP requests, the attacker gains the ability to execute arbitrary code, create or delete files, and disable services, effectively achieving full takeover of the load balancer or security appliance and the traffic it handles. All F5 BIG-IP deployments running unpatched software are affected; the provided data does not enumerate exact version ranges, which are listed in F5's May 2022 security advisory. The flaw was added to CISA's KEV catalog on 2022-05-10 with known ransomware use, and EPSS assigns a 100% probability of exploitation within 30 days (100th percentile), indicating active in-the-wild exploitation. No public proof-of-concept is catalogued in the provided data, but the KEV listing and known ransomware use confirm real-world attacks.

Do: Upgrade affected F5 BIG-IP systems to the fixed releases listed in F5's May 2022 security advisory (K23605340) immediately, prioritizing appliances whose management interface or self IPs on TCP 443 are reachable from untrusted networks; as an interim mitigation, block untrusted access to the management interface and the iControl REST service. Because this flaw is in CISA's KEV catalog with known ransomware use, also hunt for signs of compromise (unexpected files, disabled services, unknown persistence) on any system that was exposed before patching.

9.8100% KEV ransomware PoC ×4
  • F5 BIG-IP
large~10,000 internet-exposed BIG-IP systems (public scans at disclosure counted 8k-10k+), with a far larger installed base behind firewalls
CVE-2022-42475
Unauthenticated Heap Overflow in Fortinet FortiOS/FortiProxy SSL-VPN (Critical RCE)

CVE-2022-42475 is a critical (CVSS 9.8) heap-based buffer overflow in the SSL-VPN service of Fortinet FortiOS and FortiProxy. A remote, unauthenticated attacker can trigger it by sending specifically crafted requests to an exposed SSL-VPN interface, with no user interaction or credentials required. Successful exploitation yields arbitrary code or command execution on the appliance, giving attackers a foothold on the perimeter device from which they can pivot into internal networks. Any organization running the listed FortiOS (6.0 through 7.2) or FortiProxy (7.0/7.2) versions with SSL-VPN enabled is affected. Exploitation is confirmed in the wild: the flaw is in CISA KEV with known ransomware use, has near-certain exploitation probability (EPSS 99.5%), and has been used in targeted government attacks and a Chinese-nexus espionage campaign that compromised over 20,000 systems, with attackers also noted to retain access even after patching.

Do: Upgrade FortiOS and FortiProxy to fixed releases per Fortinet advisory FG-IR-22-398 (any version beyond the listed affected ranges), and reboot the appliance after patching to clear lingering SSL-VPN sessions since attackers have been observed retaining access post-patch. Check for indicators of compromise such as unknown local accounts, unexpected processes, and anomalous historical logins, and rotate SSL-VPN credentials if compromise is suspected. If SSL-VPN is not required, disable it or restrict exposure to trusted sources until patched.

9.899% KEV ransomware PoC
  • Fortinet FortiOS SSL-VPN 7.2.0 through 7.2.2, 7.0.0 through 7.0.8, 6.4.0 through 6.4.10, 6.2.0 through 6.2.11, and 6.0.15 and earlier
  • Fortinet FortiProxy SSL-VPN 7.2.0 through 7.2.1, and 7.0.7 and earlier
masshundreds of thousands of internet-exposed FortiGate/FortiProxy SSL-VPN endpoints (well over 100,000; 20,000+ confirmed victims in a single campaign)
CVE-2023-27997
Pre-Auth Heap Buffer Overflow RCE in Fortinet FortiOS/FortiProxy SSL-VPN

CVE-2023-27997 is a heap-based buffer overflow (CWE-122, with associated out-of-bounds write CWE-787) in the SSL-VPN component of Fortinet FortiOS and FortiProxy, reachable by unauthenticated users. A remote attacker can trigger it with specially crafted requests to the SSL-VPN web interface, gaining the ability to execute arbitrary code or commands on the gateway. Full control of an edge VPN/firewall appliance enables credential theft, session hijacking, and pivoting into the protected network, which makes the bug attractive to ransomware operators. Any organization exposing the SSL-VPN portal on the affected FortiOS builds (7.2.4 and below, 7.0.11 and below, 6.4.12 and below, 6.0.16 and below) or FortiProxy builds (7.2.3 and below, 7.0.9 and below, 2.0.12 and below, and 1.1/1.2 all versions) is potentially exposed. The flaw is under active exploitation: CISA added it to the KEV on 2023-06-13 with known ransomware use, EPSS estimates an ~86% probability of exploitation within 30 days (100th percentile), and reporting indicates it was likely being exploited in the wild, with Fortinet also warning that some attackers retained access to FortiGate devices even after patching.

Do: Apply Fortinet's updates to all SSL-VPN-enabled FortiOS and FortiProxy appliances as required by the CISA KEV listing, upgrading each affected branch beyond the listed versions (end-of-life FortiProxy 1.1/1.2 requires migration to a supported release); if SSL-VPN is not needed, disable the web portal or restrict it to trusted source addresses. After patching, hunt for signs of compromise and rotate credentials and VPN-related secrets, since Fortinet warned that some attackers retained access to FortiGate devices post-patching.

9.886% KEV ransomware
  • Fortinet FortiOS (SSL-VPN) 7.2.4 and below; 7.0.11 and below; 6.4.12 and below; 6.0.16 and below
  • Fortinet FortiProxy (SSL-VPN) 7.2.3 and below; 7.0.9 and below; 2.0.12 and below; 1.2 (all versions); 1.1 (all versions)
masson the order of several hundred thousand internet-exposed SSL-VPN endpoints (≈300k–500k per public scans)
CVE-2023-46747
F5 BIG-IP TMUI Authentication Bypass Enables Unauthenticated RCE

CVE-2023-46747 is a critical authentication bypass (CVSS 9.8) in the F5 BIG-IP Configuration Utility (TMUI) affecting most BIG-IP modules, including LTM, APM, DNS, AWAF, AFM, ASM, and SSL Orchestrator. By sending undisclosed, specially crafted requests to the TMUI, an attacker with network access to the BIG-IP management port and/or self IP addresses bypasses authentication and can execute arbitrary system commands on the system. No privileges or user interaction are required, and successful exploitation effectively yields full control of the affected BIG-IP deployment. Any organization running vulnerable BIG-IP software is exposed, particularly enterprises, service providers, and government agencies whose management interface or self IPs are reachable. The flaw is being actively exploited: it was added to CISA KEV on 2023-10-31 with known ransomware use, public PoC code exists, and reporting links it to Chinese nation-state actors targeting defense and government networks.

Do: Upgrade all affected BIG-IP systems to the fixed releases identified in F5 advisory K13763 (17.1.0.1, 16.1.4, 15.1.9, 14.1.5.5, or 13.1.5.1 depending on the train, or later); the CISA KEV listing makes remediation mandatory for federal agencies. As an interim mitigation, restrict network access to the TMUI management port and self IP addresses and apply F5's documented mitigation guidance. Given active nation-state and ransomware exploitation, also audit appliances for indicators of compromise such as unexpected accounts, scheduled tasks, and configuration changes.

9.897% KEV ransomware PoC ×2
  • f5 BIG-IP Access Policy Manager
  • f5 BIG-IP Advanced Firewall Manager
  • f5 BIG-IP Advanced Web Application Firewall
  • +9 more
largetens of thousands of internet-exposed BIG-IP systems (10k-100k), with a total enterprise installed base plausibly in the hundreds of thousands
CVE-2024-21762
Out-of-Bounds Write RCE in Fortinet FortiOS and FortiProxy

CVE-2024-21762 is a critical (CVSS 9.8) out-of-bounds write (CWE-787) in the SSL VPN functionality of Fortinet FortiOS and FortiProxy, allowing an unauthenticated remote attacker to execute unauthorized code or commands by sending specifically crafted requests to the vulnerable service. No authentication or user interaction is required, and network access to the SSL VPN interface is the only precondition. Organizations running affected FortiOS versions (on FortiGate appliances) or any affected FortiProxy version are exposed, particularly where the SSL VPN is internet-facing. The flaw is actively exploited: it was added to CISA's Known Exploited Vulnerabilities catalog on 2024-02-09 with ransomware use noted, EPSS puts the 30-day exploitation probability at 84.3%, and public scans suggest roughly 150,000 internet-exposed Fortinet devices may be impacted.

Do: Upgrade FortiOS and FortiProxy to fixed releases outside the affected ranges per Fortinet's advisory, prioritizing internet-facing devices; as an interim mitigation, disable SSL VPN (or SSL VPN web mode) where it is not required, per vendor and CISA guidance. After patching, check for signs of compromise and rotate credentials, since Fortinet has warned that attackers retained access to FortiGate devices post-patching. The flaw is in CISA KEV with known ransomware use, so treat this as an urgent patching priority.

9.884% KEV ransomware
  • Fortinet FortiOS 7.4.0 through 7.4.2, 7.2.0 through 7.2.6, 7.0.0 through 7.0.13, 6.4.0 through 6.4.14, 6.2.0 through 6.2.15, 6.0.0 through 6.0.17
  • Fortinet FortiProxy 7.4.0 through 7.4.2, 7.2.0 through 7.2.8, 7.0.0 through 7.0.14, 2.0.0 through 2.0.13, 1.2.0 through 1.2.13, 1.1.0 through 1.1.6, 1.0.0 through 1.0.7
mass≈150,000 internet-exposed FortiGate/FortiProxy devices (public internet-wide scans)

Indicators of compromiseAll →

TypeIndicatorContext
domainhunt.iomand-and-control (C&C) platform for remote administration,” Hunt.io says. Next, the attackers used various scripts for host dis
Full article482 words · extracted from securityweek.com · click to collapse

A threat actor targeted multiple vulnerabilities in Fortinet and F5 products to gain access to Thai broadband provider 3BB’s systems, Hunt.io reports.

The attack was discovered after the hackers left their intrusion arsenal in an open directory hosted on infrastructure in Thailand.

The directory contained 298 files across 30 subdirectories: multiple exploitation scripts, brute-force and privilege escalation tools, credential harvesting scripts, an inventory of compromised machines, and a MeshCentral instance agent configured as a persistent backdoor.

“The files were tagged across operational categories such as Exploit, Victim, Config, and History, consistent with an active staging environment,” Hunt.io notes.

The tools, the cybersecurity firm says, were crafted specifically for 3BB (Triple T Broadband), one of the largest providers of fixed-line broadband services in Thailand, with millions of users, and Jasmine, the company that previously owned Triple T Broadband.

Initial access was obtained through careful fingerprinting of a FortiGate SSL-VPN endpoint using eight shell scripts designed to determine the appliance’s firmware version, probe for vulnerabilities, and deploy exploits.

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The attackers scanned for bugs such as CVE-2018-13379, CVE-2022-42475, CVE-2023-27997, and CVE-2024-21762, confirmed the instance’s firmware version, and deployed an exploit targeting CVE-2024-21762 to achieve remote code execution (RCE).

Simultaneously, the threat actor executed a reconnaissance operation against the victim’s F5 BIG-IP instance, probing for multiple vulnerabilities, including CVE-2021-22986, CVE-2022-1388, and CVE-2023-46747, and against 3BB’s internal sales agent portal, running behind the load balancer.

Following initial access, the hackers attempted to gain root privileges on multiple Linux systems using PwnKit and Dirty COW exploits and a dedicated SUID backdoor installer.

“After successful host compromise, the actor established persistent remote access using MeshCentral as a command-and-control (C&C) platform for remote administration,” Hunt.io says.

Next, the attackers used various scripts for host discovery, remote access, and credential harvesting to move laterally across the internal 3BB environment.

They attempted to extract SSH keys, PHP configurations, database credentials, SNMP community strings, and Radius authentication data, and to perform passwordless MySQL authentication against internal databases.

Additionally, the threat actor used two scripts “to read sensitive files, deploy PHP web shells, inject SSH keys, and modify database privileges, providing multiple mechanisms for persistence and lateral movement across the environment,” Hunt.io notes.

Finally, the attackers executed a script designed to remove artifacts associated with vulnerability exploitation and backdoor deployment, along with the PHP web shells, MeshCentral deployment scripts, and system logs.

“The script concludes by verifying that persistence mechanisms remain operational, including checking the hidden SUID binary and confirming the MeshCentral service is still running. This demonstrates that the cleanup process was intended to conceal the intrusion while ensuring continued remote access to compromised systems,” Hunt.io says.

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