CVE-2020-29045

Five Star Restaurant Menu <= 2.2.0 - Unauthenticated Arbitrary Object Deserialization leading to Remote Code Execution

2021-01-11 00:00
Nick Blundell

Strategic Overview

Status
Patched in 2.2.1
Affected Plugin
Five Star Restaurant Menu and Food Ordering
Affected Version
< 2.2.1
CVSS
9.8Critical
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2020-29045
View all Five Star Restaurant Menu and Food Ordering vulnerabilities

At a glance

CVE-2020-29045 is a critical-severity Deserialization of Untrusted Data vulnerability in the Five Star Restaurant Menu and Food Ordering WordPress plugin, affecting versions < 2.2.1. 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 2.2.1; sites on affected versions should update now. Disclosed January 2021, reported by Nick Blundell.

Vulnerability Overview

The food-and-drink-menu plugin through 2.2.0 for WordPress allows remote attackers to execute arbitrary code because of an unserialize operation on the fdm_cart cookie in load_cart_from_cookie in includes/class-cart-manager.php.

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

Reaching this weakness in Five Star Restaurant Menu and Food Ordering < 2.2.1 takes no account at all. 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 Five Star Restaurant Menu and Food Ordering the fix is 2.2.1: builds < 2.2.1 are affected, anything from 2.2.1 onward is not.

Remediation

Update to version 2.2.1, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: 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: Five Star Restaurant Menu and Food Ordering 2.2.1 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Login Security

External References

https://www.cve.org/CVERecord?id=CVE-2020-29045https://www.wordfence.com/threat-intel/vulnerabilities/id/7b110a6c-fd6d-4c00-bdd6-08fce116b937https://nvd.nist.gov/vuln/detail/CVE-2020-29045

Related records

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