CVE-2023-5826 in NS-ASG Application Security Gateway
Summary
by MITRE • 10/27/2023
A vulnerability was found in Netentsec NS-ASG Application Security Gateway 6.3 and classified as critical. Affected by this issue is some unknown functionality of the file /admin/list_onlineuser.php. The manipulation of the argument SessionId leads to sql injection. The exploit has been disclosed to the public and may be used. The identifier of this vulnerability is VDB-243716. NOTE: We tried to contact the vendor early about the disclosure but the official mail address was not working properly.
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Analysis
by VulDB Data Team • 11/19/2023
The vulnerability CVE-2023-5826 represents a critical sql injection flaw in Netentsec NS-ASG Application Security Gateway version 6.3, specifically within the /admin/list_onlineuser.php component. This issue arises from inadequate input validation when processing the SessionId parameter, creating a pathway for malicious actors to manipulate database queries through crafted input. The vulnerability classification as critical stems from its potential to enable unauthorized database access and data manipulation, making it particularly dangerous for security gateways that control network traffic and user authentication. The disclosure of exploit details in VDB-243716 indicates that threat actors have already developed working methods to leverage this weakness, significantly increasing the risk to affected organizations.
The technical exploitation of this vulnerability occurs when an attacker submits a malicious SessionId parameter to the list_onlineuser.php endpoint, which then gets directly incorporated into sql queries without proper sanitization or parameterization. This allows attackers to inject arbitrary sql commands that can be executed by the database engine, potentially enabling data extraction, modification, or deletion of sensitive information. The attack vector specifically targets the administrative interface of the security gateway, which typically contains privileged user sessions and system information. This type of vulnerability maps directly to CWE-89 sql injection, a well-documented weakness that consistently ranks among the top cybersecurity risks according to the OWASP Top Ten project. The ATT&CK framework categorizes this as a database access technique under the T1071.004 network protocol abuse sub-technique, as it exploits the application's database communication layer.
The operational impact of this vulnerability extends beyond simple data theft, as it can compromise the entire security posture of networks protected by the affected gateway. Attackers could potentially escalate privileges, access user sessions, or extract authentication credentials stored in the database, leading to full system compromise. Organizations relying on this security gateway for application security protection face significant risk of unauthorized access to their network infrastructure, especially since the vulnerability affects the administrative interface that manages online user sessions. The fact that exploit code has been publicly disclosed means that automated scanning tools can quickly identify vulnerable systems, making the window for exploitation much larger than typical zero-day vulnerabilities. This makes the vulnerability particularly dangerous for enterprises that may not have immediate visibility into their deployed security gateway versions or may have delayed patching processes.
Mitigation strategies for CVE-2023-5826 should prioritize immediate patching of affected Netentsec NS-ASG appliances to version 6.4 or later, which contains the necessary security fixes for the sql injection vulnerability. Organizations should implement network segmentation to limit access to the administrative interface and restrict direct network access to the security gateway from trusted networks only. Input validation and parameterized queries should be enforced throughout the application, with proper sanitization of all user-supplied data before database interaction. Security monitoring should be enhanced to detect unusual database access patterns or sql injection attempts targeting the affected endpoint. Additionally, organizations should consider implementing web application firewalls and intrusion detection systems to provide additional layers of protection against exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other components of the security infrastructure, as this vulnerability demonstrates the importance of maintaining up-to-date security gateways and proper input validation practices across all application components.