Vulnerability identifier: #VU39804

Vulnerability risk: High

CVSSv3.1: 7.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-5539

CWE-ID: CWE-22

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
b2evolution
Web applications / CMS

Vendor: b2evolution.net

Description

The vulnerability allows a remote non-authenticated attacker to read and manipulate data.

The patch for directory traversal (CVE-2017-5480) in b2evolution version 6.8.4-stable has a bypass vulnerability. An attacker can use ../ to bypass the filter rule. Then, this attacker can exploit this vulnerability to delete or read any files on the server. It can also be used to determine whether a file exists.

Mitigation
Install update from vendor's website.

Vulnerable software versions

b2evolution: 6.8.4

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External links
http://b2evolution.net/downloads/6-8-5
http://www.securityfocus.com/bid/95700
http://github.com/b2evolution/b2evolution/commit/e35f7c195d8c1103d2d981a48cda5ab45ecac48a
http://github.com/b2evolution/b2evolution/issues/36

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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.