Yes. CISA added CVE-2015-4068 to its Known Exploited Vulnerabilities catalogue on 25 March 2022, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. Directory traversal vulnerability in Arcserve UDP allows remote attackers to obtain sensitive information or cause a denial of service. Any organisation running the affected product should treat remediation as urgent.
How CISA KEV Changes the Answer to “Exploited in the Wild”
For this CVE, the practical meaning of “yes” is not abstract. CISA’s KEV listing is the strongest public signal that the issue is being used against real systems, so the question is less about whether exploitation is possible and more about whether the vulnerable Arcserve UDP instance is still reachable, exposed, and unremediated.
That distinction matters because directory traversal flaws often become a gateway to sensitive file disclosure, configuration exposure, or follow-on operational disruption. In this case, the immediate security task is to confirm whether the product is present anywhere in your environment, whether the vulnerable service is internet-facing or reachable from untrusted internal segments, and whether the current exposure aligns with the KEV remediation expectation.
For exploitation-priority triage, use the combination of KEV status and vulnerability-management discipline to drive action. NHIMG’s Zero-Day and Exploited Vulnerabilities Guide and Vulnerability Management Guide both support the same operational point: confirmed exploitation should move the issue into emergency remediation, not routine backlog handling.
What the Arcserve UDP Directory Traversal Risk Means in Practice
Directory traversal is dangerous because it can let an attacker step outside the intended file scope and request files the application should never expose. In a backup or data-protection product, that is especially concerning because those systems often store high-value metadata, credentials, recovery artifacts, and operational configuration details.
The likely failure mode is straightforward: if the vulnerable path remains available, an attacker can probe for sensitive information, use exposed material to expand access, or disrupt the service in ways that affect backup availability and recovery confidence. Even when the initial impact looks limited to information disclosure, the downstream consequence can be broader if the exposed content helps an attacker pivot or target adjacent systems.
External reference points for that response are the CISA Known Exploited Vulnerabilities Catalog and the NIST National Vulnerability Database, which together help teams verify the record and track the vulnerability context while they work the response.
For teams that want a web-attack pattern reference, NHIMG’s Web Application Attacks Guide is the most relevant internal anchor because directory traversal is a canonical application-layer abuse pattern, even when the target is an infrastructure or backup product rather than a traditional website.
How to Respond When Patching Cannot Happen Immediately
If you cannot remediate at once, treat exposure reduction as the next-best control, not as a substitute for fixing the flaw. Reduce network reachability to the Arcserve UDP interface, restrict access to administrative paths, and verify whether any compensating control actually blocks traversal attempts rather than merely hiding the service from casual discovery.
At the same time, look for signs of earlier compromise. Review logs for suspicious requests to Arcserve endpoints, repeated path manipulation attempts, unusual reads of backup-related content, and any unexpected changes to backup jobs, retention settings, or service behavior. If sensitive information may have been exposed, consider whether administrative credentials, tokens, or other operational secrets should be rotated as a precaution.
The right external prioritisation signals here are FIRST EPSS for likelihood-based triage and the CIS Controls v8 for the broader operational discipline of asset visibility, controlled access, and timely vulnerability remediation.
For teams running broader detection or response workflows, NHIMG’s Security Data Lake Guide is useful where the question becomes how to retain and query the right telemetry at scale for compromise hunting and retrospective validation.
Risk and Threat Considerations
Because this flaw is already in CISA KEV, the main risk is not theoretical exposure but uncontained exposure. Unpatched or reachable instances may be probed opportunistically, and a backup-management product can be a high-value target because it sits close to sensitive data, recovery workflows, and administrative trust paths.
Failure mechanism: An attacker abuses traversal to step outside the intended directory boundary, then uses the resulting file access or service instability to harvest sensitive content, interfere with operations, or support follow-on intrusion.
Impact: The organisation can face disclosure of backup-related information, weakened recovery confidence, service disruption, and a wider compromise path if the exposed material helps an attacker move deeper into the environment.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | KEV-listed exploitation requires urgent vulnerability prioritisation and remediation. |
| CIS-12 — Network Infrastructure Management | Restricting reachability to the vulnerable service reduces exploitation opportunity. | |
| CIS-13 — Network Monitoring and Defense | Suspicious traversal activity requires telemetry to detect probing and compromise. | |
| Recommendation — Prioritise and remediate KEV-listed assets before routine backlog items. Limit exposure paths to the affected service and administration interfaces. Monitor for path traversal attempts and unusual reads of sensitive files. | ||
| NIST SP 800-53 Rev 5 | RA-5 — Vulnerability Monitoring and Scanning | Confirmed exploitation makes timely vulnerability identification and tracking essential. |
| SI-2 — Flaw Remediation | The core response is to correct the exploitable flaw promptly. | |
| Recommendation — Track the affected product and accelerate remediation based on exploitation evidence. Patch or mitigate the vulnerability as soon as the affected system is identified. | ||
Practitioner Guidance
What to prioritise: Confirm whether Arcserve UDP is deployed, where it is exposed, and whether any instance is still within the vulnerable operating footprint described by the vendor and KEV record. If you have multiple backup or management platforms, do not assume the risk is uniform, because products with privileged data access deserve faster treatment.
What to verify: Check whether the vulnerable interface is reachable from untrusted networks, whether logging is sufficient to reconstruct suspicious requests, and whether any sensitive file paths or administrative artifacts could have been exposed before remediation. If patching is delayed, verify that compensating controls actually block the exploit path rather than simply reducing noise.
Practitioner takeaway: Once a vulnerability is in KEV, the working assumption should be active abuse, so the decision is not whether to investigate, but how quickly you can reduce exposure, validate compromise, and restore a trusted recovery posture.
Related resources from NHI Mgmt Group
- CVE-2015-4068 (Arcserve Unified Data Protection (UDP) Directory Traversal)
- Is CVE-2015-0666 (Cisco Prime Data Center Network Manager (DCNM) Directory Traversal) being exploited in the wild?
- How do you patch or mitigate CVE-2015-0666 (Cisco Prime Data Center Network Manager (DCNM) Directory Traversal)?
- Is CVE-2015-5477 (ISC BIND Data Processing Errors) being exploited in the wild?