CVE-2017-9420

Spiffy Calendar < 3.3.0 - Reflected Cross-Site Scripting

2017-06-02 00:00

Strategic Overview

Status: Patched in 3.3.0
Affected Plugin: Spiffy Calendar
Affected Version: < 3.3.0
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2017-9420

View all Spiffy Calendar vulnerabilities

At a glance

CVE-2017-9420 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Spiffy Calendar WordPress plugin, affecting versions < 3.3.0. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.3.0; sites on affected versions should update now. Disclosed June 2017, reported by Dimitrios Tsagkarakis.

Vulnerability Overview

Cross site scripting (XSS) vulnerability in the Spiffy Calendar plugin before 3.3.0 for WordPress allows remote attackers to inject arbitrary JavaScript via the yr parameter.

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.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in Spiffy Calendar < 3.3.0 takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Spiffy Calendar the fix is 3.3.0: builds < 3.3.0 are affected, anything from 3.3.0 onward is not.

Remediation

Update to version 3.3.0, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Spiffy Calendar: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Spiffy Calendar 3.3.0 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2017-9420 https://www.wordfence.com/threat-intel/vulnerabilities/id/f78e6faf-ff1d-4944-aa54-7843cc8614f4 https://nvd.nist.gov/vuln/detail/CVE-2017-9420

Related records

Same weakness class

Other vulnerabilities in Spiffy Calendar

CVSS Vector

6.1

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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