Vulnerability identifier: #VU21923

Vulnerability risk: Low

CVSSv3.1: 5.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:P/RL:U/RC:C]

CVE-ID: CVE-2019-17207, CVE-2019-16521

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Broken Link Checker
Web applications / Modules and components for CMS

Vendor: Janis Elsts, Vladimir Prelovac

Description

The disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.

The vulnerability exists due to improper encoding and insertion of an HTTP GET parameter into HTML. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website, such as exploit the filter function on the page listing all detected broken links by providing an XSS payload in the "s_filter" GET parameter in the "filter_id=search" request.

Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform phishing and drive-by-download attacks.

PoC:

https://<host>/wp-admin/tools.php?page=view-broken-links&filter_id=search&s_filter=%22+id%3D%22blc-links%22%3E%3Cscript%3Ealert%281%29%3C%2Fscript%3E

Mitigation
Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

Vulnerable software versions

Broken Link Checker: 0.1 - 1.11.8

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External links
http://github.com/sbaresearch/advisories/tree/public/2019/SBA-ADV-20190913-02_WordPress_Plugin_Broken_Link_Checker
http://wordpress.org/plugins/broken-link-checker/#developers

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.