CVE-2024-4358: Progress Telerik Report Server Authentication Bypass by Spoofing Vulnerability

CVE-2024-4358 is an authentication bypass by spoofing vulnerability in Progress Telerik Report Server. It allows an attacker to obtain unauthorized access to the product. For IT and security teams, this matters because Report Server often holds or generates sensitive business reports; unauthorized access can lead to data exposure, further lateral movement, or misuse of reporting capabilities. Confirm all product-specific details against the vendor advisory before acting.

How it works

The flaw is classified as CWE-290, Authentication Bypass by Spoofing. In this class of weakness, an attacker can spoof or forge authentication-related information so that the system incorrectly treats the request as legitimate. The CISA summary states that Progress Telerik Report Server contains an authorization bypass by spoofing vulnerability that allows an attacker to obtain unauthorized access. Public detail on exact request formats, headers, or parameters is limited; defenders should treat any unauthenticated or weakly authenticated interface to the Report Server as potentially abusable until the vendor advisory is reviewed. Successful abuse grants the attacker a foothold with the privileges the spoofed identity would normally hold, without needing valid credentials.

Am I affected? How to find it in your systems

Progress Telerik Report Server is typically deployed as a dedicated reporting service, often on Windows servers or in internal application tiers that generate, store, or serve business reports. It may be exposed to internal users, partner portals, or (less commonly) the internet. Inventory steps:

• Search asset inventories, CMDB records, and software deployment tools for “Telerik Report Server,” “Progress Telerik,” or related service names and install paths.
• Scan internal networks for hosts listening on ports commonly used by the product and inspect process lists or installed programs for Report Server components.
• Review configuration files and management consoles for the product version and authentication settings. Compare installed versions and configurations against the vendor advisory to determine which are affected; do not rely on version numbers not listed in that advisory.
• Check authentication and access logs for unexpected successful logins, sessions created without corresponding credential events, or access from unusual source addresses. Telemetry signs of exploitation for this class include sudden unauthenticated access to report endpoints, creation of new administrative or privileged sessions, and anomalous report generation or download activity. Correlate with identity-provider logs if the product is integrated with SSO or directory services.

If the product is present, treat it as potentially vulnerable until the advisory confirms otherwise.

How to remediate

Patch first. Apply the vendor update or mitigations named in the Progress advisory for CVE-2024-4358. CISA’s required action is to apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. After patching:

• Verify the update is installed and the service restarts cleanly.
• Re-test authentication paths to confirm the bypass is no longer possible.
• Harden the remaining surface: enforce strong authentication (preferably multi-factor or certificate-based where supported), restrict management interfaces to trusted networks, and ensure least-privilege accounts are used for report generation and viewing.
• Review and rotate any credentials or API keys that may have been exposed during the vulnerable period.

Document the change and update asset inventories so future scans correctly reflect the remediated state.

If you can't patch immediately

Until the vendor update can be applied, reduce risk with compensating controls:

• Network segmentation: place Report Server behind strict firewall rules or a zero-trust gateway so only authorized clients and jump hosts can reach it. Block direct internet exposure if present.
• Virtual patching or WAF rules: if a web application firewall or reverse proxy sits in front of the service, implement rules that reject anomalous authentication or authorization requests characteristic of spoofing attempts. Confirm rule efficacy against the vendor’s description of the issue.
• Disable or restrict the affected feature: if the product allows temporary disablement of remote authentication endpoints, report publishing, or unauthenticated access paths, do so while maintaining business continuity for critical reports.
• Heightened monitoring: enable detailed authentication and access logging, forward logs to a SIEM, and alert on successful access without prior credential validation, new privileged sessions, or bulk report downloads. Increase review frequency of those alerts.
• If mitigations cannot be applied and risk is unacceptable, follow CISA guidance and discontinue use of the product until a fix is available.

These measures lower likelihood and impact but do not replace the vendor patch.

If your data may have been exposed

Vulnerabilities that grant unauthorized access can lead to data breaches if exploited. Known ransomware use associated with this CVE is not documented. If you suspect compromise, isolate affected hosts, preserve logs, and begin incident response focused on report data, credentials, and any downstream systems the Report Server could reach. As a quick personal check, individuals can run a free exposure scan of their email address against known breach data sets to see whether their credentials appear in public dumps; organizational teams should perform broader credential and data-exposure reviews. Confirm all findings and next steps against the vendor advisory and your internal incident procedures.