CVE-2017-20208

RegistrationMagic - Custom Registration Forms <= 3.7.9.2 - PHP Object Injection

2017-10-02 00:00
Brad Haas

Strategic Overview

Status
Patched in 3.7.9.3
Affected Plugin
RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login
Affected Version
< 3.7.9.3
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2017-20208
View all RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login vulnerabilities

At a glance

CVE-2017-20208 is a critical-severity Deserialization of Untrusted Data vulnerability in the RegistrationMagic WordPress plugin, affecting versions < 3.7.9.3. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 3.7.9.3; sites on affected versions should update now. Disclosed October 2017, reported by Brad Haas.

Vulnerability Overview

The RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login plugin for WordPress is vulnerable to PHP Object Injection in all versions up to 3.7.9.3 (exclusive) via deserialization of untrusted input from the is_expired_by_date() function. This makes it possible for unauthenticated attackers to inject a PHP Object. The additional presence of a POP chain allows attackers to fetch a remote file and install it on the site.

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 privileges on the target site, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

RegistrationMagic < 3.7.9.3 carries this weakness at is_expired_by_date(), and reaching it takes a caller who can reach the endpoint. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For RegistrationMagic the fix is 3.7.9.3: builds < 3.7.9.3 are affected, anything from 3.7.9.3 onward is not.

Remediation

Update to version 3.7.9.3, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to RegistrationMagic: 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: RegistrationMagic 3.7.9.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2017-20208https://www.wordfence.com/threat-intel/vulnerabilities/id/c2b79193-f8fc-4ea2-8973-fe292cfb926bhttps://nvd.nist.gov/vuln/detail/CVE-2017-20208

Related records

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