CVE-2021-25082

Popup Builder <= 4.0.6 - Local File Inclusion and PHAR Deserialization

2022-01-24 00:00
ZhongFu Su

Strategic Overview

Status
Patched in 4.0.7
Affected Plugin
Popup Builder – Create highly converting, mobile friendly marketing popups.
Affected Version
< 4.0.7
CVSS
8.8High
Weakness type
CWE-98 · Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')
CVE
CVE-2021-25082
View all Popup Builder – Create highly converting, mobile friendly marketing popups. vulnerabilities

At a glance

CVE-2021-25082 is a high-severity Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion') vulnerability in the Popup Builder WordPress plugin, affecting versions < 4.0.7. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). The issue is fixed in version 4.0.7; sites on affected versions should update now. Disclosed January 2022, reported by ZhongFu Su.

Vulnerability Overview

The Popup Builder WordPress plugin before 4.0.7 does not validate and sanitise the sgpb_type parameter before using it in a require statement, leading to a Local File Inclusion issue. Furthermore, since the beginning of the string can be controlled, the issue can lead to RCE vulnerability via wrappers such as PHAR

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program ('PHP Remote File Inclusion')

Reaching this weakness in Popup Builder < 4.0.7 takes a caller who can reach the endpoint. PHP file inclusion means a path used by include or require is built from request data, so the file that gets executed is under the caller's influence.

Including an attacker-influenced file executes its contents, which is why this class is routinely chained with an upload or log-poisoning step to reach code execution. For Popup Builder the fix is 4.0.7: builds < 4.0.7 are affected, anything from 4.0.7 onward is not.

Remediation

Update to version 4.0.7, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Popup Builder: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Popup Builder 4.0.7 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-25082https://www.wordfence.com/threat-intel/vulnerabilities/id/5d096d29-6fdb-4f89-91d3-9ebfc1169f0dhttps://nvd.nist.gov/vuln/detail/CVE-2021-25082

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C