Vulnerability identifier: #VU23954

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-2019-20204

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Postie
Web applications / Modules and components for CMS

Vendor: Wayne Allen

Description

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

The vulnerability exists due to insufficient sanitization of user-supplied data. 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.

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:

Use Polyglot JavaScript syntax with crafted SVG, as follows:

jaVasCript:/*--></title></style></textarea></script></xmp><svg/onload='+/"/+/onmouseover=1/+/[*/[]/+alert(1)//'>

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

Vulnerable software versions

Postie: 1.1.5 - 1.9.40

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External links
http://github.com/V1n1v131r4/Exploiting-Postie-WordPress-Plugin-/blob/master/README.md
http://postieplugin.com/
http://wordpress.org/plugins/postie/#developers
http://wpvulndb.com/vulnerabilities/10002

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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.