CVE-2025-5462: Ivanti Connect Secure DOS Vulnerability

CVE-2025-5462 Overview

A heap-based buffer overflow vulnerability has been identified in multiple Ivanti products, including Connect Secure, Policy Secure, ZTA Gateway, and Neurons for Secure Access. This vulnerability allows a remote unauthenticated attacker to trigger a denial of service condition by exploiting improper bounds checking in heap memory allocation. The flaw exists in versions prior to the patched releases and poses a significant risk to organizations relying on these products for secure remote access and zero trust network architecture.

Critical Impact

Remote unauthenticated attackers can cause denial of service, potentially disrupting critical VPN and secure access infrastructure for enterprise environments.

Affected Products

• Ivanti Connect Secure before version 22.7R2.8 or 22.8R2
• Ivanti Policy Secure before version 22.7R1.5
• Ivanti ZTA Gateway before version 22.8R2.3-723
• Ivanti Neurons for Secure Access before version 22.8R1.4

Discovery Timeline

• August 12, 2025 - CVE-2025-5462 published to NVD
• September 23, 2025 - Last updated in NVD database

Technical Details for CVE-2025-5462

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow), a memory corruption flaw that occurs when a program writes data beyond the boundaries of a heap-allocated buffer. In the context of Ivanti's secure access products, this vulnerability can be exploited remotely without authentication, making it particularly dangerous for internet-facing VPN gateways and secure access infrastructure.

The heap-based buffer overflow occurs when specially crafted network requests cause the affected application to write data past the allocated heap buffer boundaries. While the immediate impact is limited to denial of service (affecting availability), heap overflows can sometimes be leveraged for more severe attacks depending on memory layout and exploitation techniques.

Root Cause

The root cause of CVE-2025-5462 is improper bounds checking during heap memory operations. When processing certain network input, the affected Ivanti products fail to properly validate the size of incoming data against the allocated buffer size. This oversight allows an attacker to overflow the heap buffer, corrupting adjacent memory structures and causing the application to crash or become unresponsive.

Attack Vector

The attack vector for this vulnerability is network-based with no authentication or user interaction required. An attacker can remotely send malicious requests to the affected Ivanti appliances to trigger the heap overflow condition. The vulnerability affects the availability of the system by causing a denial of service.

The exploitation mechanism involves sending crafted network packets that cause the heap buffer to overflow. When the application processes these packets, it writes beyond the allocated memory region, corrupting heap metadata or adjacent data structures. This typically results in application crashes or service unavailability. For detailed technical information, refer to the Ivanti Security Advisory.

Detection Methods for CVE-2025-5462

Indicators of Compromise

• Unexpected service crashes or restarts of Ivanti Connect Secure, Policy Secure, or ZTA Gateway services
• Application core dumps or memory-related error logs indicating heap corruption
• Unusual patterns of connection attempts followed by service unavailability
• Increased memory usage anomalies preceding service failures

Detection Strategies

• Monitor Ivanti appliance logs for heap corruption errors, segmentation faults, or unexpected process terminations
• Implement network intrusion detection rules to identify malformed or anomalous traffic patterns targeting Ivanti services
• Deploy SentinelOne Singularity platform with behavioral analysis to detect exploitation attempts and service disruption patterns
• Review web application firewall logs for suspicious request patterns that may indicate exploitation attempts

Monitoring Recommendations

• Enable verbose logging on all affected Ivanti appliances and centralize log collection for correlation analysis
• Configure alerting for service availability metrics including unexpected restarts and high memory utilization
• Implement network traffic analysis for connections to Ivanti appliances to detect anomalous request volumes or patterns
• Establish baseline behavior for Ivanti services to identify deviations that may indicate exploitation attempts

How to Mitigate CVE-2025-5462

Immediate Actions Required

• Inventory all Ivanti Connect Secure, Policy Secure, ZTA Gateway, and Neurons for Secure Access deployments in your environment
• Verify current version numbers against affected version ranges and prioritize patching for internet-facing appliances
• Review network segmentation to limit exposure of vulnerable Ivanti appliances pending patch deployment
• Enable enhanced logging and monitoring on all affected systems to detect potential exploitation attempts

Patch Information

Ivanti has released security patches addressing this vulnerability. Organizations should upgrade to the following minimum versions:

• Ivanti Connect Secure: Version 22.7R2.8 or 22.8R2 or later
• Ivanti Policy Secure: Version 22.7R1.5 or later
• Ivanti ZTA Gateway: Version 22.8R2.3-723 or later
• Ivanti Neurons for Secure Access: Version 22.8R1.4 or later (Fix deployed on August 2, 2025)

For complete patch details and installation instructions, refer to the Ivanti August Security Advisory.

Workarounds

• Implement rate limiting and connection throttling at the network perimeter to reduce the impact of potential denial of service attempts
• Deploy a web application firewall (WAF) with rules to inspect and filter potentially malicious traffic destined for Ivanti appliances
• Consider temporary network isolation of vulnerable appliances to trusted network segments only while patches are being deployed
• Enable IP allowlisting where feasible to restrict access to known trusted sources

# Example: Network-level rate limiting using iptables (temporary mitigation)
# Limit new connections to Ivanti appliance ports
iptables -A INPUT -p tcp --dport 443 -m state --state NEW -m limit --limit 50/minute --limit-burst 100 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -m state --state NEW -j DROP