Virtual private networks are designed to provide secure remote access to enterprise resources. However, when the authentication mechanisms protecting a VPN gateway are compromised, the same trusted connection used by employees can become an entry point for attackers. This is particularly dangerous when the intrusion takes place through an organization’s existing remote-access infrastructure, where malicious activity can initially resemble legitimate business traffic.
As per a report from Cyber Security News, ransomware operators are actively exploiting CVE-2026-0257, an authentication-bypass vulnerability affecting Palo Alto Networks PAN-OS GlobalProtect and Prisma Access. Threat intelligence investigations have identified activity involving the Qilin and Settra ransomware groups, which are using the flaw to establish unauthorized VPN sessions and gain access to internal networks.
The campaign highlights a critical security challenge: gaining access through a trusted VPN can give attackers an opportunity to steal credentials, discover internal systems, move laterally, and prepare ransomware deployment before defenders recognize the intrusion.
CVE-2026-0257 carries a CVSS score of 7.8 and a High severity rating in Palo Alto Networks’ advisory. The vulnerability allows a remote, unauthenticated attacker to bypass security restrictions and establish an unauthorized VPN connection.
The flaw involves GlobalProtect authentication override cookies, which allow users to maintain authentication across supported GlobalProtect components without repeatedly entering their credentials.
The vulnerability becomes exploitable when authentication override cookies are enabled and the relevant certificate configuration allows the cookie protection mechanism to be abused. In particular, reusing a certificate between the HTTPS service and authentication override cookie operations can expose the deployment to the attack.
The vulnerability does not affect every deployment. Exposure depends on the configuration of the GlobalProtect portal or gateway and its authentication override settings.
The attack begins at the remote-access perimeter, where GlobalProtect provides connectivity between external users and internal enterprise resources. By exploiting the authentication bypass, an attacker can establish a VPN session without possessing the legitimate user’s credentials.
Once connected, the attacker can use the trusted network path to investigate accessible systems and identify opportunities for further compromise. The resulting traffic may resemble ordinary remote access, making it harder to distinguish the intrusion from legitimate employee activity using connection logs alone.
The broader attack progression can be represented as:
GlobalProtect authentication bypass → Unauthorized VPN session → Internal network discovery → Credential theft and lateral movement → Data collection or exfiltration → Potential ransomware deployment
Threat intelligence reporting has also identified related activity involving Cobalt Strike, BloodHound, and SharpHound. These tools can support post-compromise operations, including command execution, environment discovery, and Active Directory relationship mapping. Their presence does not mean every exploitation attempt uses all three tools, but it reinforces the importance of investigating activity after an unexpected VPN connection.
A successful VPN connection is not, by itself, evidence that the connecting user is legitimate. Attackers who bypass authentication can inherit the appearance of an authorized remote session, making perimeter-only monitoring insufficient.
The more useful indicators emerge from the activity that follows the connection. An unfamiliar VPN session followed by unusual directory queries, access to administrative systems, unexpected authentication attempts, or connections to multiple internal hosts can reveal a larger intrusion.
Security teams should therefore correlate VPN authentication records with identity activity, endpoint behavior, internal network connections, and changes to privileged accounts. This allows analysts to identify whether a remote-access event is consistent with the user’s normal behavior or represents the beginning of a broader compromise.
The vulnerability affects specified releases across PAN-OS 12.1, 11.2, 11.1, and 10.2, as well as Prisma Access 11.2 and 10.2. Administrators should consult Palo Alto Networks’ official advisory for the exact affected maintenance releases and corresponding fixed versions. Panorama and Cloud NGFW are not affected by this vulnerability.
Organizations should prioritize the following actions:
Priority | Recommended Action |
Immediate | Identify all GlobalProtect portals and gateways that may be exposed to CVE-2026-0257. |
Patch | Upgrade affected deployments to the appropriate vendor-fixed releases. |
Configuration | Disable authentication override cookies where they are not required. |
Certificate security | Generate a dedicated certificate exclusively for authentication override cookies. Do not reuse portal, gateway, or other service certificates. |
Deployment coverage | Verify that all relevant internal and external portals and gateways have been updated, including affected on-premises components in hybrid Prisma Access environments. |
Threat hunting | Investigate unexpected VPN sessions and subsequent internal network activity. |
Incident response | Review credential exposure, privileged access, lateral movement, and potential ransomware preparation if exploitation is suspected. |
Patching must account for interactions between GlobalProtect components that generate or accept authentication cookies. Incomplete upgrades can create cookie compatibility issues, so administrators should follow the vendor’s deployment guidance and verify that all relevant components are updated.
Preventing exploitation is essential, but organizations also need visibility into what happens when an attacker successfully establishes an unauthorized connection. Seceon’s security capabilities can help correlate activity across the endpoint, identity, network, and cloud layers to support investigation and response.
aiSIEM helps security teams collect and correlate telemetry from multiple sources to identify suspicious activity across the environment. In a GlobalProtect incident, this can help connect an unusual remote-access session with subsequent authentication events, internal reconnaissance, access to sensitive systems, and suspicious outbound communication.
The objective is to move beyond an isolated VPN alert and establish a timeline of the activity associated with the session. Correlating these events helps analysts determine whether an apparent remote login is followed by behavior consistent with unauthorized access.
Once attackers gain network access, they may attempt to execute commands, obtain credentials, establish persistence, or move between endpoints. aiXDR-PMax provides endpoint detection and response capabilities that can help identify suspicious process execution, malware activity, privilege escalation, and other post-compromise behavior.
For example, an unauthorized VPN connection followed by unusual command execution or credential-access activity on an internal endpoint should be investigated as a potentially connected incident. Endpoint telemetry adds the execution-level context needed to understand what the attacker is doing beyond the network perimeter.
Organizations that connect their internal networks to cloud infrastructure need to consider whether an attacker could use compromised access to reach cloud resources. aiSIEM-CGuard extends Seceon’s security capabilities into cloud and SaaS environments, helping organizations maintain visibility across connected infrastructure.
When suspicious remote access coincides with abnormal cloud identity activity or unexpected access to cloud resources, correlating those events can help security teams investigate whether the intrusion has extended beyond the original network.
aiSecurityScore360 supports security posture and exposure assessment, helping organizations understand weaknesses that may increase their overall attack surface. For this incident, the priority is to identify exposed remote-access infrastructure, assess relevant security weaknesses, and prioritize remediation based on risk.
While posture assessment does not replace patching or live threat detection, it can help organizations establish a clearer picture of their exposure and strengthen their approach to risk reduction.
aiBAS360 can support controlled attack simulation and security-control validation. Organizations can use breach and attack simulation to evaluate whether their defensive processes identify relevant attack techniques and whether response workflows operate as expected.
This is particularly useful for testing the detection and response capabilities surrounding unauthorized access, internal reconnaissance, credential compromise, and lateral movement. Validation helps determine whether security controls work as intended rather than assuming that deploying them automatically guarantees protection.
The GlobalProtect campaign demonstrates why security teams must investigate the full sequence of activity associated with remote access.
VPN session → Identity and endpoint correlation → Internal network investigation → Threat validation → Coordinated response
A successful connection should not automatically be treated as a successful authentication of a legitimate user. Context from identity, endpoint, network, and cloud telemetry can help establish whether the session represents normal business activity or an intrusion.
For organizations operating hybrid environments, this approach is particularly important because remote-access infrastructure often connects users to systems with different levels of sensitivity. An attacker who gains access through one gateway may attempt to use that connectivity to reach resources that were never intended to be accessible from the internet.
The exploitation of CVE-2026-0257 by ransomware actors highlights the growing risk associated with trusted remote-access infrastructure. By abusing authentication override cookie configurations, attackers can establish unauthorized VPN sessions without valid credentials and potentially use those sessions as a starting point for internal reconnaissance, credential theft, lateral movement, and ransomware operations.
Organizations should prioritize patching affected GlobalProtect and Prisma Access deployments, review authentication override cookie configurations, use dedicated certificates for cookie protection, and investigate suspicious sessions for signs of post-compromise activity.
For defense teams, the broader lesson is that securing remote access requires more than protecting the VPN gateway. It also requires visibility into what happens after a connection is established.
By combining aiSIEM, aiXDR-PMax, aiSIEM-CGuard, aiSecurityScore360, and aiBAS360, organizations can strengthen detection, correlate activity across security layers, assess exposure, and validate their response readiness. The goal is to identify unauthorized access earlier, understand its potential impact, and prevent an initial VPN compromise from developing into a wider enterprise incident.
