Thursday, May 8, 2025
Homecyber securityChinese Hackers Exploit Ivanti Connect Secure Flaw to Gain Unauthorized Access

Chinese Hackers Exploit Ivanti Connect Secure Flaw to Gain Unauthorized Access

Published on

SIEM as a Service

Follow Us on Google News

In a sophisticated cyber-espionage operation, a group known as UNC5221, suspected to have China-nexus, has exploited a critical vulnerability in Ivanti Connect Secure VPN appliances.

The exploit, identified as CVE-2025-22457, represents a stack-based buffer overflow affecting multiple Ivanti products, including Policy Secure and Zero Trust Access gateways.

A Critical Flaw Initially Underestimated

CVE-2025-22457 was initially classified as a low-risk denial-of-service bug by Ivanti.

- Advertisement - Google News

However, further analysis revealed its potential for unauthenticated remote code execution (RCE), leading Ivanti to publicly disclose the vulnerability on April 3, 2025, and upgrade its severity to Critical with a CVSS score of 9.0.

Despite issuing a patch in February, UNC5221 managed to reverse-engineer it, understanding the underlying vulnerability to create a sophisticated exploit.

This exploit allows attackers to send specially crafted HTTP requests to vulnerable appliances, triggering a buffer overflow and executing arbitrary code with high privileges, effectively opening a gateway to the victim’s internal network.

UNC5221’s Advanced Tactics

Once inside, UNC5221 deploys a multi-stage malware sequence. Initially, a shell script dropper executes on the compromised device, orchestrating the loading of malicious code.

This code then injects a backdoor into the running Ivanti Connect Secure web service process, ensuring persistence without saving any files to disk.

Known as BRUSHFIRE, this backdoor remains covert, existing only in memory and responding to specific inbound VPN traffic.

The group’s tactics extend to evasion, employing techniques like in-memory malware implants, log tampering, and the use of compromised intermediary devices to obscure their operational infrastructure.

According to Picus Security, this approach significantly reduces the chances of detection by typical monitoring systems, allowing UNC5221 to maintain a foothold for espionage activities.

UNC5221’s campaign has not been limited to a specific region; it has impacted organizations worldwide, including U.S.-based targets.

The exploit’s reach underscores the global threat posed by such vulnerabilities in network infrastructure, especially those accessible from the internet.

Ivanti has reported that several customers were breached due to this vulnerability, emphasizing the urgency for all users to update to the patched version (ICS 22.7R2.6 or later).

In response, security experts recommend immediate patching to the latest version, vigilant monitoring for unauthorized access attempts, and implementing additional security measures like network segmentation to limit the attack surface.

Organizations should also consider revising their authentication and password management practices to mitigate risks from stolen credentials.

This incident highlights the persistent threat from state-sponsored actors focusing on internet-facing devices and underscores the importance of rapid response to software vulnerabilities, especially in critical infrastructure like VPN gateways, which serve as primary entry points for cyber adversaries.

Aman Mishra
Aman Mishra
Aman Mishra is a Security and privacy Reporter covering various data breach, cyber crime, malware, & vulnerability.

Latest articles

Top Ransomware Groups Target Financial Sector, 406 Incidents Revealed

Flashpoint analysts have reported that between April 2024 and April 2025, the financial sector...

Agenda Ransomware Group Enhances Tactics with SmokeLoader and NETXLOADER

The Agenda ransomware group, also known as Qilin, has been reported to intensify its...

SpyCloud Analysis Reveals 94% of Fortune 50 Companies Have Employee Data Exposed in Phishing Attacks

SpyCloud, the leading identity threat protection company, today released an analysis of nearly 6...

PoC Tool Released to Detect Servers Affected by Critical Apache Parquet Vulnerability

F5 Labs has released a new proof-of-concept (PoC) tool designed to help organizations detect...

Resilience at Scale

Why Application Security is Non-Negotiable

The resilience of your digital infrastructure directly impacts your ability to scale. And yet, application security remains a critical weak link for most organizations.

Application Security is no longer just a defensive play—it’s the cornerstone of cyber resilience and sustainable growth. In this webinar, Karthik Krishnamoorthy (CTO of Indusface) and Phani Deepak Akella (VP of Marketing – Indusface), will share how AI-powered application security can help organizations build resilience by

Discussion points


Protecting at internet scale using AI and behavioral-based DDoS & bot mitigation.
Autonomously discovering external assets and remediating vulnerabilities within 72 hours, enabling secure, confident scaling.
Ensuring 100% application availability through platforms architected for failure resilience.
Eliminating silos with real-time correlation between attack surface and active threats for rapid, accurate mitigation

More like this

Top Ransomware Groups Target Financial Sector, 406 Incidents Revealed

Flashpoint analysts have reported that between April 2024 and April 2025, the financial sector...

Agenda Ransomware Group Enhances Tactics with SmokeLoader and NETXLOADER

The Agenda ransomware group, also known as Qilin, has been reported to intensify its...

PoC Tool Released to Detect Servers Affected by Critical Apache Parquet Vulnerability

F5 Labs has released a new proof-of-concept (PoC) tool designed to help organizations detect...