Researchers Identify Multiple China Hacker Groups Exploiting Ivanti Security Flaws
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2024-21887 +1 in the same advisory: …46805 | Command Injection RCE in Ivanti Connect Secure and Policy Secure Ivanti Connect Secure (formerly Pulse Connect Secure) and Ivanti Policy Secure appliances contain a command injection flaw (CWE-77) in their web components, triggered when an authenticated administrator sends crafted requests to the appliance. The bug can be chained with the separate authentication bypass CVE-2023-46805, allowing an unauthenticated attacker to achieve the same result. Successful exploitation lets an attacker execute arbitrary commands and code on the appliance, providing a foothold into the networks behind the VPN or network access control gateway. Any organization running these appliances, typically enterprises and government agencies often deployed directly on the internet perimeter, is affected. Exploitation is confirmed in the wild: the flaw was added to CISA's Known Exploited Vulnerabilities catalog on 2024-01-10 with known ransomware use and EPSS assigns a 100% probability of exploitation within 30 days, although no public proof-of-concept is available. Do: Apply Ivanti's mitigations or patched builds immediately per vendor instructions, addressing the chained authentication bypass CVE-2023-46805 at the same time, and discontinue or restrict use of any appliance for which mitigations are unavailable, especially if it is internet-facing. Because exploitation with ransomware use is known, assume compromise is possible: review appliance web logs for suspicious requests and run Ivanti's integrity-checking guidance to verify appliance images before and after remediation. Where feasible, restrict direct internet exposure of the appliance web interface and monitor for further vendor advisories. | 9.1 group max | 100% | KEV ransomware PoC |
| largetens of thousands of appliances (roughly 20,000-30,000 internet-exposed ICS gateways at disclosure; total deployed base likely higher) | |
| CVE-2024-21893 | SSRF in Ivanti Connect Secure, Policy Secure, and Neurons SAML Component CVE-2024-21893 is a server-side request forgery (SSRF) vulnerability in the SAML component of Ivanti Connect Secure (formerly Pulse Connect Secure), Ivanti Policy Secure, and Ivanti Neurons. A remote attacker can trigger the flaw with crafted unauthenticated requests to the SAML component, causing the appliance to make requests to otherwise restricted resources. Successful exploitation allows the attacker to access certain restricted resources without any credentials, and CISA notes the flaw has been used in ransomware operations. Any organization running an affected Ivanti Connect Secure, Policy Secure, or Neurons deployment is exposed, particularly where the appliance is reachable from the internet. The vulnerability is confirmed exploited in the wild: it was added to CISA's Known Exploited Vulnerabilities catalog on 2024-01-31, carries an EPSS probability of 100%, and no public proof-of-concept is known. Do: Apply Ivanti's released patches or the vendor-issued mitigations immediately per vendor instructions, or discontinue use of the product if mitigations are unavailable, as required by CISA. Because ransomware use is documented, review SAML-related logs and appliance audit trails for signs of exploitation and follow-on compromise, and check for indicators of post-exploitation activity. Monitor Ivanti advisories for patched version numbers and updated mitigation guidance, since specific fixed versions are not yet specified in the available data. | 8.2 | 100% | KEV ransomware |
| largetens of thousands of internet-exposed appliances (with total user counts likely in the hundreds of thousands) |
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Multiple China-nexus threat actors have been linked to the zero-day exploitation of three security flaws impacting Ivanti appliances (CVE-2023-46805, CVE-2024-21887, and CVE-2024-21893).
The clusters are being tracked by Mandiant under the uncategorized monikers UNC5221, UNC5266, UNC5291, UNC5325, UNC5330, and UNC5337. Also previously linked to the exploitation spree is a Chinese hacking crew called UNC3886, whose tradecraft is notable for weaponizing zero-day bugs in Fortinet and VMware to breach target networks.
The Google Cloud subsidiary said it has also observed financially motivated actors exploiting CVE-2023-46805 and CVE-2024-21887, likely in an attempt to conduct cryptocurrency mining operations.
"UNC5266 overlaps in part with UNC3569, a China-nexus espionage actor that has been observed exploiting vulnerabilities in Aspera Faspex, Microsoft Exchange, and Oracle Web Applications Desktop Integrator, among others, to gain initial access to target environments," Mandiant researchers said.
The threat actor has been linked to post-exploitation activity leading to the deployment of the Sliver command-and-control (C2) framework, a variant of the WARPWIRE credential stealer, and a new Go-based backdoor dubbed TERRIBLETEA that comes with command execution, keylogging, port scanning, file system interaction, and screen capturing functions.
UNC5330, which has been observed combining CVE-2024-21893 and CVE-2024-21887 to breach Ivanti Connect Secure VPN appliances at least since February 2024, has leveraged custom malware such as TONERJAM and PHANTOMNET for facilitating post-compromise actions -
- PHANTOMNET - A modular backdoor that communicates using a custom communication protocol over TCP and employs a plugin-based system to download and execute additional payloads
- TONERJAM - A launcher that's designed to decrypt and execute PHANTOMNET
Besides using Windows Management Instrumentation (WMI) to perform reconnaissance, move laterally, manipulate registry entries, and establish persistence, UNC5330 is known to compromise LDAP bind accounts configured on the infected devices in order to domain admin access.
Another notable China-linked espionage actor is UNC5337, which is said to have infiltrated Ivanti devices as early as January 2024 using CVE-2023-46805 and CVE-2024 to deliver a custom malware toolset known as SPAWN that comprises four distinct components that work in tandem to function as a stealthy and persistent backdoor -
- SPAWNSNAIL - A passive backdoor that listens on localhost and is equipped to launch an interactive bash shell as well as launch SPAWNSLOTH
- SPAWNMOLE - A tunneler utility that's capable of directing malicious traffic to a specific host while passing benign traffic unmodified to the Connect Secure web server
- SPAWNANT - An installer that's responsible for ensuring the persistence of SPAWNMOLE and SPAWNSNAIL by taking advantage of a coreboot installer function
- SPAWNSLOTH - A log tampering program that disables logging and log forwarding to an external syslog server when the SPAWNSNAIL implant is running
Mandiant has assessed with medium confidence that UNC5337 and UNC5221 are one and the same threat group, noting the SPAWN tool is "designed to enable long-term access and avoid detection."
UNC5221, which was previously attributed to web shells such as BUSHWALK, CHAINLINE, FRAMESTING, and LIGHTWIRE, has also unleashed a Perl-based web shell referred to as ROOTROT that's embedded into a legitimate Connect Secure .ttc file located at "/data/runtime/tmp/tt/setcookie.thtml.ttc" by exploiting CVE-2023-46805 and CVE-2024-21887.
A successful deployment of the web shell is followed by network reconnaissance and lateral movement, in some cases, resulting in the compromise of a vCenter server in the victim network by means of a Golang backdoor called BRICKSTORM.
"BRICKSTORM is a Go backdoor targeting VMware vCenter servers," Mandiant researchers explained. "It supports the ability to set itself up as a web server, perform file system and directory manipulation, perform file operations such as upload/download, run shell commands, and perform SOCKS relaying."
The last among the five China-based groups tied to the abuse of Ivanti security flaws is UNC5291, which Mandiant said likely has associations with another hacking group UNC3236 (aka Volt Typhoon), primarily owing to its targeting of academic, energy, defense, and health sectors.
"Activity for this cluster started in December 2023 focusing on Citrix Netscaler ADC and then shifted to focus on Ivanti Connect Secure devices after details were made public in mid-Jan. 2024," the company said.
The findings once again underscore the threat faced by edge appliances, with the espionage actors utilizing a combination of zero-day flaws, open-source tooling, and custom backdoors to tailor their tradecraft depending on their targets to evade detection for extended periods of time.
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