#VU40733 Cross-site scripting in Moodle - CVE-2015-3178

Vulnerability identifier: #VU40733

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2015-3178

CWE-ID: CWE-79

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Moodle
Web applications / Other software

Vendor: moodle.org

Description

Vulnerability allows a remote attacker to perform Cross-site scripting attacks.

An input validation error exists in the external_format_text function in lib/externallib.php in Moodle through 2.5.9, 2.6.x before 2.6.11, 2.7.x before 2.7.8, and 2.8.x before 2.8.6. A remote authenticated attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in victim's browser in security 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.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Moodle: 2.5 - 2.5.8, 2.6 - 2.6.10, 2.7 - 2.7.7, 2.8 - 2.8.5

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External links
https://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-49718
https://openwall.com/lists/oss-security/2015/05/18/1
https://www.securityfocus.com/bid/74726
https://www.securitytracker.com/id/1032358
https://moodle.org/mod/forum/discuss.php?d=313685

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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.