DokuWiki 2018-04-22a Greebo Arbitrary Code Execution

DokuWiki version 2018-04-22a Greebo suffers from a CSV formula injection vulnerability that allows for arbitrary code execution.

MD5 | da11d55a03deb277ad0e944efc15402f

SEC Consult Vulnerability Lab Security Advisory < 20180906-0 >
title: CSV Formula Injection
product: DokuWiki
vulnerable version: 2018-04-22a "Greebo" and older versions
fixed version: None
CVE number: CVE-2018-15474
impact: Medium
found: 2018-07-09
by: Jean-Benjamin Rousseau (Office Zurich)
SEC Consult Vulnerability Lab

An integrated part of SEC Consult
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Vendor description:
"DokuWiki is a simple to use and highly versatile Open Source wiki software
that doesn't require a database. It is loved by users for its clean and
readable syntax. The ease of maintenance, backup and integration makes it
an administrator's favorite. Built in access controls and authentication
connectors make DokuWiki especially useful in the enterprise context
and the large number of plugins contributed by its vibrant community allow
for a broad range of use cases beyond a traditional wiki."


Business recommendation:
The issue will not be fixed according to the vendor. Users are advised
to be careful when opening files via the CSV export functionality.

SEC Consult recommends to perform a thorough security review conducted by
security professionals to identify and resolve all security issues.

Vulnerability overview/description:
1) CSV Formula Injection vulnerability
The administration panel of the application has a "CSV export of users"
feature which allows the export of user data (username, real name,
email address and user groups) as a CSV file. On the registration page,
it is possible for an attacker to set certain values in the Real Name field
that - when exported and opened with a spreadsheet application
(Microsoft Excel, Open Office, etc.) - will be interpreted as a formula.
This puts the administrators who open those malicious exported files at risk.
Exfiltration of sensitive data or even the execution of arbitrary code
on the local machine of the victim will be the result. The final impact
depends on the used spreadsheet software on the client of the victim.

Proof of concept:
1) CSV Formula Injection vulnerability
Registration URL:

When the registration request is submitted, the following parameters are sent
in a POST request:


The "fullname" parameter is not sanitized before being stored and during
the CSV export. An attacker can inject different CSV formula
payloads in the fullname parameter.
For example:
=cmd|'/C calc'!A0

As soon as the file gets opened in Microsoft Excel, the program calc.exe is
launched. Different warnings might pop up. However, these warnings are usually
ignored because the file comes from a trusted source.

Vulnerable / tested versions:
The latest version 2018-04-22a "Greebo" has been tested:

Also found to be vulnerable:
2017-02-19 stable release
2016-06-26 stable release
2015-08-10 stable release
2014-09-29 stable release
2014-05-05 stable release
2013-12-08 stable release

Vendor contact timeline:
2018-07-18: Contacting vendor through [email protected]
2018-07-18: Vendor replied, they asked for the advisory without encryption
2018-07-19: Advisory sent without encryption
2018-07-19: Vendor replied with no intention to fix the vulnerability
2018-07-30: Reminder sent to the vendor. No reply
2018-08-20: Ask for updates to the vendor
2018-08-20: Vendor replied that no patch will be provided
2018-09-06: Public release of security advisory

The issue will not be fixed according to the vendor:


Advisory URL:


SEC Consult Vulnerability Lab

SEC Consult
Europe | Asia | North America

About SEC Consult Vulnerability Lab
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EOF Jean-Benjamin Rousseau / @2018

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