Iranian Hackers Exploiting VPN Flaws to Backdoor Organizations Worldwide
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| 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. | 9.8 | 100% | KEV ransomware |
| mass≈500,000 internet-exposed FortiOS SSL VPN portals (Fortinet cited ~480,000 affected devices) | |
| CVE-2019-11510 | Unauthenticated Arbitrary File Read in Ivanti Pulse Connect Secure VPN Ivanti Pulse Connect Secure, an enterprise SSL VPN appliance, contains an arbitrary file read vulnerability (CWE-22, path traversal) that requires no authentication. An unauthenticated remote attacker with network access to the appliance over HTTPS can send a specially crafted URI containing traversal sequences to read arbitrary files from the device. The attacker gains access to sensitive appliance files, potentially including configuration or credential material useful for further compromise, and CISA records known ransomware use of this flaw. Any organization running Pulse Connect Secure, especially gateways exposed to the internet for remote access, is affected. Exploitation is established: CISA added the flaw to its Known Exploited Vulnerabilities catalog on 2021-11-03 with known ransomware use, EPSS assigns a 100% probability of exploitation in the next 30 days, and no public PoC is known. Do: Apply updates per Ivanti's instructions, the required action in the CISA KEV entry, prioritizing internet-facing Pulse Connect Secure gateways, and consult the vendor advisory for the applicable fixed release since no version range is provided here. Where patching is not immediate, restrict HTTPS access to the appliance and hunt for signs of exploitation (unexpected file reads, anomalous VPN logins or sessions, and follow-on ransomware activity), as CISA reports known ransomware use. | 10.0 | 100% | KEV ransomware PoC ×2 |
| largeTens of thousands of internet-exposed gateways (order of 10,000-100,000 systems; each typically serves hundreds of VPN users, so potentially millions of users) | |
| CVE-2019-1579 | Format String RCE in Palo Alto Networks PAN-OS GlobalProtect Portal/Gateway CVE-2019-1579 is a remote code execution vulnerability (CWE-134, format string) in Palo Alto Networks PAN-OS that is exposed on devices where the GlobalProtect Portal or GlobalProtect Gateway interface is enabled. An attacker can trigger it remotely by sending specially crafted format-string input to the network-facing GlobalProtect portal or gateway interface. Successful exploitation allows arbitrary code execution on the firewall, giving the attacker control of the device and a foothold into the protected network. Any organization running PAN-OS with the GlobalProtect Portal or Gateway interface enabled is affected; deployments without those interfaces enabled are not exposed to this flaw. Exploitation is confirmed: the vulnerability is in CISA's KEV (added 2022-01-10) with known ransomware use, and EPSS assigns a 46.2% probability of exploitation within 30 days (99th percentile), although no public PoC is catalogued. Do: Upgrade PAN-OS per Palo Alto Networks' security advisory, as required by CISA's KEV required action; first inventory devices with the GlobalProtect Portal or Gateway interface enabled and prioritize internet-facing ones. Until patched, restrict or firewall access to the GlobalProtect interfaces, and hunt for signs of compromise given the known ransomware association. | 8.1 | 46% | KEV ransomware PoC |
| largetens of thousands of internet-exposed GlobalProtect portals/gateways (likely more including internally deployed gateways) | |
| CVE-2019-19781 | Unauthenticated path traversal RCE in Citrix ADC, Gateway, and SD-WAN WANOP CVE-2019-19781 is a path-traversal flaw (classified CWE-22, though CISA's description calls it unspecified) in Citrix ADC (formerly NetScaler ADC), Citrix Gateway, and Citrix SD-WAN WANOP appliances that lets an unauthenticated remote attacker traverse directories via crafted requests and execute arbitrary commands on the appliance, typically with root privileges. It is triggered by sending specially crafted directory-traversal requests (crafted URLs/requests to the appliance's management or VPN endpoints), which lets the attacker write files and run commands with no credentials. Successful exploitation yields arbitrary code execution on the appliance, enabling theft of VPN/ADC credentials, lateral movement into the corporate network, and installation of persistent backdoors. Any organization running affected ADC, Gateway, or SD-WAN WANOP firmware is affected, with internet-facing gateways used for remote access at the highest risk. Exploitation is confirmed in the wild: the vulnerability is on CISA's KEV (added 2021-11-03) with known ransomware use, EPSS assigns near-certain (100.0%) probability of exploitation within 30 days, and no public PoC is listed despite confirmed abuse. Do: Upgrade Citrix ADC, Gateway, and SD-WAN WANOP appliances to the fixed firmware builds listed in Citrix advisory CTX267020; if patching cannot be done immediately, apply Citrix's published interim mitigation and restrict internet exposure to the appliance. Because exploitation grants root code execution and persistence, after patching hunt for indicators of compromise (unexpected nsroot account, modified system files, crontab/scheduled entries), kill all active and inactive sessions, and rotate appliance and VPN credentials. Prioritize internet-facing gateways and comply with CISA's required action to apply vendor updates. | 9.8 | 100% | KEV ransomware |
| massroughly 80,000-100,000+ internet-exposed Citrix ADC/Gateway appliances at the time of disclosure, with a far larger total installed base (including… |
Full article682 words · extracted from thehackernews.com · click to collapse
Ravie LakshmananFeb 18, 2020
A new report published by cybersecurity researchers has unveiled evidence of Iranian state-sponsored hackers targeting dozens of companies and organizations in Israel and around the world over the past three years.
Dubbed "Fox Kitten," the cyber-espionage campaign is said to have been directed at companies from the IT, telecommunication, oil and gas, aviation, government, and security sectors.
"We estimate the campaign revealed in this report to be among Iran's most continuous and comprehensive campaigns revealed until now," ClearSky researchers said.
"The revealed campaign was used as a reconnaissance infrastructure; however, it can also be used as a platform for spreading and activating destructive malware such as ZeroCleare and Dustman."
Tying the activities to threat groups APT33, APT34, and APT39, the offensive — conducted using a mix of open source and self-developed tools — also facilitated the groups to steal sensitive information and employ supply-chain attacks to target additional organizations, the researchers said.
Exploiting VPN Flaws to Compromise Enterprise Networks
The primary attack vector employed by the Iranian groups has been the exploitation of unpatched VPN vulnerabilities to penetrate and steal information from target companies. The prominent VPN systems exploited this way included Pulse Secure Connect (CVE-2019-11510), Palo Alto Networks' Global Protect (CVE-2019-1579), Fortinet FortiOS (CVE-2018-13379), and Citrix (CVE-2019-19781).
ClearSky noted that the hacking groups were able to successfully acquire access to the targets' core systems, drop additional malware, and laterally spread across the network by exploiting "1-day vulnerabilities in relatively short periods of time."
Upon successfully gaining an initial foothold, the compromised systems were found to communicate with attacker-control command-and-control (C2) servers to download a series of custom VBScript files that can, in turn, be used to plant backdoors.
Furthermore, the backdoor code in itself is downloaded in chunks so as to avoid detection by antivirus software installed on the infected computers. It's the job of a separate downloaded file — named "combine.bat" — to stitch together these individual files and create an executable.
To perform these tasks and achieve persistence, the threat actors exploited tools such as Juicy Potato and Invoke the Hash to gain high-level privileges and laterally move across the network. Some of the other tools developed by the attackers include:
- STSRCheck - A tool for mapping databases, servers, and open ports in the targeted network and brute-force them by logging with default credentials.
- Port.exe - A tool to scan predefined ports and servers.
Once the attackers gained lateral movement capabilities, the attackers move to the final stage: execute the backdoor to scan the compromised system for relevant information and exfiltrate the files back to the attacker by establishing a remote desktop connection (using a self-developed tool called POWSSHNET) or opening a socket-based connection to a hardcoded IP address.
In addition, the attackers used web shells in order to communicate with the servers located inside the target and upload files directly to a C2 server.
The Work of Multiple Iranian Hacking Groups
Based on the campaign's use of web shells and overlaps with the attack infrastructure, the ClearSky report highlighted that the attacks against VPN servers are possibly linked to three Iranian groups — APT33 ("Elfin"), APT34 ("OilRig") and APT39 (Chafer).
What's more, the researchers assessed that the campaign is a result of a "cooperation between the groups in infrastructure," citing similarities in the tools and work methods across the three groups.
Just last month, Iranian state-backed hackers — dubbed "Magnallium" — were discovered carrying out password-spraying attacks targeting US electric utilities as well as oil and gas firms.
Given that the attackers are weaponizing VPN flaws within 24 hours, it's imperative that organizations install security patches as and when they are available.
Aside from following the principle of least privilege, it also goes without saying that critical systems are monitored continuously and kept up to date. Implementing two-step authentication can go a long way towards minimizing unauthorized logins.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://thehackernews.com/2020/02/iranian-hackers-vpn-vulnerabilities.html