CVE-2024-34070: Blind XSS Leading to Froxlor Application Compromise

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 1.0%, percentile 62: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 62% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
• Only applies if your dependency tree includes froxlor/froxlor (Composer (PHP)) < 2.1.9, fixed in 2.1.9. Check your lockfile, including transitive dependencies.

What it is

Froxlor is open source server administration software. Prior to 2.1.9, a Stored Blind Cross-Site Scripting (XSS) vulnerability was identified in the Failed Login Attempts Logging Feature of the Froxlor Application. An unauthenticated User can inject malicious scripts in the loginname parameter on the Login attempt, which will then be executed when viewed by the Administrator in the System Logs. By exploiting this vulnerability, the attacker can perform various malicious actions such as forcing the Administrator to execute actions without their knowledge or consent. For instance, the attacker can force the Administrator to add a new administrator controlled by the attacker, thereby giving the attacker full control over the application. This vulnerability is fixed in 2.1.9.

From the GitHub advisory

Description:

A Stored Blind Cross-Site Scripting (XSS) vulnerability has been identified in the Failed Login Attempts Logging Feature of the Froxlor Application. Stored Blind XSS occurs when user input is not properly sanitized and is stored on the server, allowing an attacker to inject malicious scripts that will be executed when other users access the affected page. In this case, an unauthenticated User can inject malicious scripts in the loginname parameter on the Login attempt, which will then be executed when viewed by the Administrator in the System Logs.

The application protects users against XSS attacks by utilizing an xss sanitization library. But the checks of the library were bypassed by crafting an XSS Payload using data binding and interpolation of Vue.js

A working XSS payload was crafted which forces an administrator to add a new malicious attacker-controlled Administrator User. The Payload is: payload.txt

By exploiting this vulnerability, an unauthenticated attacker can force the Administrator to perform actions without the administrator even noticing anything suspicious. In one scenario, I made an exploit that forced the administrator to add an attacker-controlled Administrator into the Froxlor Application, resulting in a compromise of the Froxlor Application.

Weakness type: CWE-79, CWE-80.

Product: froxlor/froxlor (Composer (PHP)) · Assigned by: GitHub_M · Published: 2024-05-10

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Privileges required: none (no login)
• User interaction: required (a user must click/open something)
• Scope: changed (can affect other components)

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.97% probability of exploitation activity in the next 30 days; percentile 62.

Timeline

• 2024-05-10 — CVE record published by GitHub_M
• 2024-05-10 — GitHub-reviewed advisory GHSA-x525-54hf-xr53 published (critical)
• 2024-08-02 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-x525-54hf-xr53 github.com
2. CVE.org record CVE-2024-34070 cve.org
3. NVD entry CVE-2024-34070 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com

Critical Composer (PHP) advisories · Today’s Security Digest