CVE-2022-35254 is a high-severity use-after-free vulnerability (CWE-416) affecting multiple Ivanti products, specifically Ivanti Connect Secure (ICS), Ivanti Policy Secure (IPS), and Ivanti Neurons for Zero Trust Access Gateway. The vulnerability exists in versions prior to ICS 9.1R14.3, 9.1R15.2, 9.1R16.2, 22.2R1, and 22.2R4; IPS versions prior to 9.1R17 and 22.3R1; and Ivanti Neurons for Zero Trust Access Gateway versions prior to 22.3R1. This vulnerability allows an unauthenticated attacker to trigger a denial-of-service (DoS) condition by exploiting a use-after-free flaw. Use-after-free vulnerabilities occur when a program continues to use a pointer after the memory it points to has been freed, potentially leading to crashes or other unpredictable behavior. In this case, the attacker does not require any authentication or user interaction, and the attack can be launched remotely over the network (CVSS vector AV:N/AC:L/PR:N/UI:N). The impact is limited to availability, as the vulnerability does not affect confidentiality or integrity. Exploitation results in a denial-of-service, causing the affected Ivanti gateway products to crash or become unresponsive, disrupting secure remote access and zero-trust access services. There are no known public exploits in the wild as of the published date (December 5, 2022), but the vulnerability has been recognized and enriched by CISA, indicating its importance. The affected products are critical components in enterprise network security, providing VPN, policy enforcement, and zero-trust access capabilities. Given the unauthenticated remote attack vector and the critical role these products play in secure access, this vulnerability poses a significant risk to organizations relying on Ivanti's secure access solutions.

For European organizations, the impact of CVE-2022-35254 can be substantial. Ivanti Connect Secure, Policy Secure, and Neurons for Zero Trust Access Gateway are widely used in enterprises to provide secure remote access, VPN services, and zero-trust network access. A successful denial-of-service attack could disrupt business continuity by preventing employees and partners from securely accessing internal resources, especially in the context of increased remote work and hybrid environments. This disruption could affect critical sectors such as finance, healthcare, government, and manufacturing, where secure access is essential. Additionally, prolonged downtime could lead to operational delays, loss of productivity, and potential regulatory compliance issues related to availability of critical services. Although the vulnerability does not allow data theft or manipulation, the availability impact alone can cause significant operational and reputational damage. Furthermore, the unauthenticated nature of the exploit means attackers do not need valid credentials, increasing the risk of opportunistic attacks or targeted campaigns against organizations using these Ivanti products.

1. Immediate patching: Organizations should prioritize updating affected Ivanti products to the fixed versions: ICS versions 9.1R14.3, 9.1R15.2, 9.1R16.2, 22.2R4 or later; IPS versions 9.1R17 and 22.3R1 or later; and Ivanti Neurons for Zero Trust Access Gateway 22.3R1 or later. 2. Network segmentation: Limit exposure of Ivanti gateway devices by placing them behind firewalls and restricting access to trusted IP ranges where possible, reducing the attack surface. 3. Monitoring and alerting: Implement enhanced monitoring on Ivanti gateway devices to detect unusual traffic patterns or repeated connection attempts that could indicate exploitation attempts. 4. Incident response readiness: Prepare incident response plans specifically for denial-of-service scenarios affecting secure access infrastructure to minimize downtime and restore services quickly. 5. Vendor communication: Maintain active communication with Ivanti for any additional advisories or patches and subscribe to threat intelligence feeds for updates on exploitation attempts. 6. Access control hardening: Where feasible, enforce multi-factor authentication and limit administrative access to Ivanti devices to reduce risk from secondary attacks during downtime. 7. Backup and redundancy: Ensure redundant Ivanti gateway deployments and regular configuration backups to enable rapid failover and recovery in case of service disruption.