CVE-2019-25740: Joomla com_jsjobs Arbitrary File Deletion Vulnerability

Technical summary

CVE-2019-25740 is a path traversal vulnerability (CWE-22) in the com_jsjobs component for Joomla 1.2.6. The vulnerability exists in the job.savejob task handler, which processes POST requests containing custom user field parameters. Specifically, the field_2 parameter fails to sanitize path traversal sequences (such as ../ or absolute paths). An authenticated attacker can submit specially crafted POST requests that traverse the file system and delete arbitrary files accessible to the web server process. The CVSS 3.1 base score is 6.5 (Medium severity), reflecting high confidentiality impact due to the ability to manipulate file system state through authenticated access with no user interaction required.

Business impact

Successful exploitation could result in data loss, service disruption, or corruption of Joomla installation integrity. An attacker with valid credentials—whether a disgruntled employee, compromised account, or external actor who has gained login access—can systematically delete critical files, website content, configuration files, or backups. This could lead to site downtime, data recovery costs, and potential compliance violations if regulated data is affected. Organizations relying on Joomla job posting functionality face heightened risk if user accounts are not carefully managed.

Affected systems

Joomla installations running the com_jsjobs extension version 1.2.6 are vulnerable. The component is a job posting/management module, so primarily affects Joomla sites using job board functionality. Any user with valid authentication credentials (registered user, staff member, administrator) can exploit this flaw. The vulnerability does not require administrative privileges, only valid login, making it exploitable by lower-privileged users or accounts that have been compromised.

Exploitability

This vulnerability requires authentication, which significantly raises the barrier compared to unauthenticated exploits. However, the attack is straightforward once a valid account exists: an attacker sends a POST request to the job.savejob task with path traversal payloads in the field_2 parameter. No complex interaction, social engineering, or user action is needed—it is a direct server-side operation. Exploit complexity is low. The vulnerability is not currently tracked in CISA's Known Exploited Vulnerabilities (KEV) catalog, but the technical simplicity means exploit code could be developed quickly if the flaw becomes widely known.

Remediation

Update the com_jsjobs extension to a patched version released after 1.2.6. Verify the exact patch version against the official Joomla extensions repository or vendor advisory. Additionally, review access controls: limit job posting component access to trusted users only, regularly audit user accounts for unauthorized or dormant credentials, and enforce strong password policies. Consider temporarily disabling the com_jsjobs extension if a patch is not immediately available or if the component is not essential to operations.

Patch guidance

Check the official Joomla extensions marketplace or the com_jsjobs developer's repository for an update version released after 1.2.6. Apply patches during a maintenance window after testing in a non-production environment. Verify that the patch addresses input validation and path traversal filtering in the field_2 parameter handling. If the extension is no longer maintained, consider migrating to an actively supported alternative job posting solution.

Detection guidance

Monitor POST requests to the job.savejob task for unusual field_2 parameter values containing path traversal sequences (../, ..\, /, absolute paths). Log all user actions within the job posting component, especially deletions and file operations. Review web server and Joomla access logs for requests from unexpected IP ranges or accounts. Set up alerts for sudden file deletions in critical directories (configuration, backup, content directories). Conduct a file integrity check on deployed Joomla installations to identify unauthorized deletions that may have occurred.

Why prioritize this

Although the CVSS score is medium (6.5), this vulnerability warrants prompt attention because: (1) it enables unauthorized file deletion, a destructive action with high business impact; (2) exploitation is simple and requires only standard authentication; (3) affected files could include configuration, backups, or core content; (4) the flaw affects a commonly used job board extension; and (5) malicious insiders or credential-compromised accounts can exploit it without advanced technical skill. Organizations should prioritize patching within 1–2 weeks, particularly if user accounts are numerous or not tightly controlled.

Risk score, explained

The CVSS 3.1 score of 6.5 reflects: Attack Vector = Network (remote exploitation possible), Attack Complexity = Low (no special conditions), Privileges Required = Low (valid authentication needed), User Interaction = None (automatic exploitation), Scope = Unchanged, and Confidentiality = High (ability to affect file state and potentially read deleted or replaced content). Integrity and Availability impacts depend on which files are deleted; the base metric assumes high confidentiality risk from successful path traversal and file system manipulation. The score does not account for organizational factors such as whether job posting is mission-critical or how carefully credentials are managed.

Frequently asked questions