CVE-2022-20948 is a significant vulnerability discovered in the web management interface of Cisco BroadWorks Hosted Thin Receptionist (HTR). This bug allows authenticated, remote attackers to perform Cross-Site Scripting (XSS) attacks. If exploited, an attacker could make the victim’s browser run malicious scripts, potentially stealing sensitive information or manipulating the interface.
In this exclusive deep dive, we'll explore the root cause, how attackers exploit it, see a real-world code snippet, and wrap up with defense strategies. If you manage Cisco BroadWorks HTR, read and patch now!
Vulnerability Name: Reflected Cross-Site Scripting (XSS) in BroadWorks HTR
- CVE: CVE-2022-20948
Impact: Arbitrary JavaScript code execution, sensitive data theft, session hijacking
- Cisco Advisory: cisco-sa-bws-htr-xss-dWJQwerT
What is XSS?
Cross-Site Scripting (XSS) lets attackers inject scripts into webpages viewed by other users. Reflected XSS, in particular, tricks users into clicking on a malicious link that bounces their data right back as part of the page, executing code inside their browser.
Why Did This Happen?
The Cisco BroadWorks Hosted Thin Receptionist did not *properly validate user-submitted input*. Malicious payloads sent as parameters were directly reflected on the page, unescaped.
Attacker crafts a special URL with a malicious script in a parameter.
2. Victim, already authenticated, clicks the link (e.g., sent via email, chat, or social engineering).
3. Malicious script executes in the context of the HTR interface in the victim’s browser, allowing the attacker to act as the user.
Example Exploit Code Snippet
Let’s suppose the vulnerable page is https://htr.example.com/page?message=. An attacker might craft a URL like:
https://htr.example.com/page?message=<script>alert('XSS')</script>
If the application prints the message parameter to the web page directly (without sanitization), the script will trigger when the user visits the URL.
Example vulnerable PHP snippet (not actual HTR code, but illustrative)
// DO NOT USE - FOR EDUCATION ONLY
$message = $_GET['message'];
echo "<div>Welcome! $message</div>";
Suppose the victim clicks the crafted link, and their browser sees
<div>Welcome! <script>alert('XSS')</script></div>
*The alert will pop up, confirming script execution.*
`js
`
- Session Hijack (if cookies not HTTPOnly)
- Interface Manipulation (fake forms, redirects)
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## The Attack Flow Step by Step
1. Create a malicious URL:
Attacker includes a payload in a HTR interface parameter.
2. Trick a user (needs to be logged in) into clicking the link.
3. Script executes in the interface under the logged-in user's account.
4. Attacker can:
- Steal sensitive data
- Hijack sessions (if cookies are accessible)
- Modify what the user sees or does
### Visualization
!XSS Flow Chart
*Source: OWASP* (see more)
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## Real-World Impact
- Data Theft: Sensitive receptionist info, contact lists, or schedules could be stolen.
- Session Abuse: If cookies/session tokens are not both HTTPOnly/Secure, attacker can impersonate users.
- Phishing: User interface can be altered to collect more credentials.
- Persistence: Further attacks, like injecting more persistent XSS or dropping redirects.
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## Original References
- Cisco Security Advisory: cisco-sa-bws-htr-xss-dWJQwerT
- NVD Listing for CVE-2022-20948
- OWASP XSS Overview
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## How To Defend
You MUST apply Cisco’s updates. There are no suggested workarounds from Cisco.
Other best practices for all web apps:
- Always escape and sanitize user input (use HTML encoding and proper libraries)
- Implement Content Security Policy (CSP)
- Set ‘HttpOnly’ and ‘Secure’ flags on cookies
- Educate users not to trust strange links
Remember: Because the vulnerability requires authentication, it won’t be exploited via Google search, but if attackers know who your receptionists are, they may target them directly.
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## Conclusion
CVE-2022-20948 is a classic example of how missing input validation creates an open door for attackers. While Cisco BroadWorks Hosted Thin Receptionist is popular in hosted communication services, the potential for sensitive data theft and UI manipulation is serious.
Patch your HTR systems immediately!
Do not assume users—especially busy receptionist staff—won’t click unfamiliar links, especially if well-crafted.
Stay safe, and follow official Cisco channels for advisories and patch information.
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*All code snippets and explanations here are for educational purposes only. Never test exploits on systems you don’t own or have permission to evaluate.*
Timeline
Published on: 11/15/2024 16:15:24 UTC
Last modified on: 11/18/2024 17:11:56 UTC