CVE-2021-24684

PDF Light Viewer <= 1.4.11 - Authenticated Command Injection

2021-09-15 00:00

Strategic Overview

Status: Patched in 1.4.12
Affected Plugin: WordPress PDF Light Viewer Plugin
Affected Version: <= 1.4.11
CVSS: 9.9Critical
Weakness type: CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CVE: CVE-2021-24684

View all WordPress PDF Light Viewer Plugin vulnerabilities

At a glance

CVE-2021-24684 is a critical-severity Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability in the WordPress PDF Light Viewer Plugin WordPress plugin, affecting versions <= 1.4.11. It carries a CVSS score of 9.9 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account. The issue is fixed in version 1.4.12; sites on affected versions should update now. Disclosed September 2021, reported by apple502j.

Vulnerability Overview

The WordPress PDF Light Viewer Plugin WordPress plugin before 1.4.12 allows users with Author roles to execute arbitrary OS command on the server via OS Command Injection when invoking Ghostscript.

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 interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Remediation

Update to version 1.4.12, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to WordPress PDF Light Viewer Plugin: 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: WordPress PDF Light Viewer Plugin 1.4.12 closes this, and updating the plugin is the step that ends it.

Firewall
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Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24684 https://www.wordfence.com/threat-intel/vulnerabilities/id/491240c5-2045-4e0b-9916-4337946d2653 https://nvd.nist.gov/vuln/detail/CVE-2021-24684

CVSS Vector

9.9

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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