CVE-2021-24964

LiteSpeed Cache <= 4.4.3 - Authorization Bypass

2021-11-30 00:00
Emil Kylander

Strategic Overview

Status
Patched in 4.4.4
Affected Plugin
LiteSpeed Cache
Affected Version
1.0.15 – 4.4.3
CVSS
6.5Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2021-24964
View all LiteSpeed Cache vulnerabilities

At a glance

CVE-2021-24964 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the LiteSpeed Cache WordPress plugin, affecting versions 1.0.15 – 4.4.3. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.4.4; sites on affected versions should update now. Disclosed November 2021, reported by Emil Kylander.

Vulnerability Overview

The LiteSpeed Cache WordPress plugin before 4.4.4 does not properly verify that requests are coming from QUIC.cloud servers, allowing attackers to make requests to certain endpoints by using a specific X-Forwarded-For header value. In addition, one of the endpoint could be used to set CSS code if a setting is enabled, which will then be output in some pages without being sanitised and escaped. Combining those two issues, an unauthenticated attacker could put Cross-Site Scripting payloads in pages visited by users.

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

Reaching this weakness in LiteSpeed Cache 1.0.15 – 4.4.3 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 LiteSpeed Cache the fix is 4.4.4: builds 1.0.15 – 4.4.3 are affected, anything from 4.4.4 onward is not.

Remediation

Update to version 4.4.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to LiteSpeed Cache: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: LiteSpeed Cache 4.4.4 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24964https://www.wordfence.com/threat-intel/vulnerabilities/id/a82bffab-77c3-48e8-af84-39709bf0353bhttps://nvd.nist.gov/vuln/detail/CVE-2021-24964

Related records

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