CVE-2020-28976

Canto <= 1.9.0 - Blind Server-Side Request Forgery via detail.php

2020-12-04 00:00

Strategic Overview

Status: Patched in 2.0.1
Affected Plugin: Canto
Affected Version: <= 1.9.0
CVSS: 8.3High
Weakness type: CWE-918 · Server-Side Request Forgery (SSRF)
CVE: CVE-2020-28976

At a glance

CVE-2020-28976 is a high-severity Server-Side Request Forgery (SSRF) vulnerability in the Canto WordPress plugin, affecting versions <= 1.9.0. It carries a CVSS score of 8.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.0.1; sites on affected versions should update now. Disclosed December 2020, reported by Pankaj Verma.

Vulnerability Overview

The Canto plugin 1.9.0 for WordPress contains a blind SSRF vulnerability. It allows an unauthenticated attacker can make a request to any internal and external server via /includes/lib/detail.php?subdomain=SSRF.

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.

CWE-918: Server-Side Request Forgery (SSRF)

Reaching this weakness in Canto <= 1.9.0 takes a caller who can reach the endpoint. Server-side request forgery means the application fetches a URL supplied by the caller, turning the server into a proxy for requests the attacker could not make directly.

The request originates from inside the hosting network, which is how these flaws reach cloud metadata endpoints, internal admin panels and services that trust local traffic. For Canto the fix is 2.0.1: builds <= 1.9.0 are affected, anything from 2.0.1 onward is not.

Remediation

Update to version 2.0.1, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Canto: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Canto 2.0.1 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-28976 https://www.wordfence.com/threat-intel/vulnerabilities/id/5781420d-b1e0-435f-8bf2-193cc7b095ed https://nvd.nist.gov/vuln/detail/CVE-2020-28976

Related records

Same weakness class

Other vulnerabilities in Canto

CVSS Vector

8.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityLow

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