How do you patch or mitigate CVE-2020-8657 (EyesOfNetwork Use of Hard-Coded Credentials)?

CISA’s required action for CVE-2020-8657 is to apply updates per vendor instructions. In practice, find every instance of EyesOfNetwork EyesOfNetwork in your estate, apply the vendor security update or documented mitigation, and if no fix can be applied, remove internet exposure or take the product out of service. After patching, review logs for signs of earlier exploitation, because attackers used this flaw in the wild.

What you are fixing when CVE-2020-8657 is in scope

CVE-2020-8657 is a hard-coded credential problem, so the real issue is not just applying a version update. You are remediating a trust failure in the product’s authentication path, which means any exposed deployment, reused credential, or lingering administrative access path has to be treated as part of the fix. If the product cannot be safely patched, the risk can only be reduced by removing exposure or retiring the instance.

The right first step is to find every EyesOfNetwork deployment, confirm whether it is internet-facing or otherwise reachable from untrusted networks, and then treat the vendor update as the preferred remedy. For this class of flaw, patching without checking deployment scope often leaves the same credential available to an attacker through another route. Use the vendor advisory and CISA Known Exploited Vulnerabilities Catalog to verify the required action and any timing constraints.

Because the flaw involves hard-coded credentials, mitigation is also about removing any assumption that the exposed secret is still unknown. That means reviewing whether the product was ever configured with shared administrative access, whether backups or cloned images preserved the same secret, and whether any dependent systems trusted that credential for automation or support access. If the deployment pattern is unclear, the safest response is to assume the credential may already have been discovered.

How to reduce exposure if you cannot patch immediately

If the vendor fix cannot be applied right away, the mitigation priority is to shrink the reachable attack surface. Take the product out of service if possible, or at minimum remove internet exposure and confine access to tightly controlled administrative paths. For a hard-coded credential issue, a firewall alone is not a complete control, but it can buy time while you plan repair or decommissioning.

Where the system must remain online, verify whether any local or upstream controls can prevent direct access to the vulnerable interface, and prefer a compensating control that is observable and reversible. Zero-Day and Exploited Vulnerabilities Guide is useful here because this situation behaves like an emergency vulnerability response problem: triage first, mitigate exposure second, and only then normalise the patch process.

If the product is embedded in a larger monitoring or operations stack, document every dependency before changing anything. Hard-coded credentials often survive through scripts, integration jobs, and legacy admin workflows, so taking a system offline can have wider operational impact than teams expect. That is why removal from service should be planned as a controlled change, not an unstructured shutdown.

When exposure is reduced but not eliminated, treat the remaining window as a hunt-and-contain period. Review logs, authentication records, and administrative actions for signs that the product was accessed before remediation, especially if the instance was externally reachable. The goal is to determine whether the flaw was merely present or whether it was already used.

What to check after patching or containment

After applying the vendor security update or implementing a documented mitigation, validate that the vulnerable instance is no longer reachable in the same way, and confirm that the old access path no longer works. If the flaw exposed a reusable login or administrative secret, rotate any associated credentials and invalidate sessions or tokens that could have been created with it. Even where the vendor fix succeeds, the access material should be treated as compromised until proven otherwise.

Post-fix review should focus on compromise evidence, not just patch status. Look for unexpected logins, configuration changes, new local users, unusual scheduled tasks, or outbound activity that does not fit the system’s normal behaviour. Because attackers used this flaw in the wild, the absence of an exploit alert is not enough to close the case; you need enough telemetry to show whether the product was touched before the fix.

If you discover signs of earlier abuse, widen the review to adjacent systems that may have reused the same administrative pattern, credential store, or trust relationship. A hard-coded credential problem can become a lateral movement problem when the same secret is reused across environments or support tooling. Guide to the Secret Sprawl Challenge is a good companion reference for understanding why hard-coded credentials so often become broader exposure events.

Risk and Threat Considerations

Hard-coded credentials are attractive to attackers because they bypass normal user lifecycle controls and often remain valid for as long as the product or image exists. If the affected system is internet-facing, the flaw can be discovered and abused without any prior foothold, which makes speed of containment more important than perfect patch sequencing.

Failure mechanism: The product’s embedded secret can be extracted or reused, allowing an attacker to authenticate as a trusted actor rather than exploit a complex chain of weaknesses.

Impact: That can lead to unauthorized administrative access, configuration tampering, data exposure, or use of the system as a pivot point into connected infrastructure.

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-4 — Secure Configuration of Enterprise Assets and Software	Exposed hard-coded creds demand secure configuration and exposure reduction.
	CIS-5 — Account Management	Hard-coded credentials require identifying and controlling affected accounts and access paths.
	CIS-6 — Access Control Management	Mitigation relies on restricting reachability when patching is delayed.
Recommendation — Harden or remove exposed EyesOfNetwork instances and validate configuration changes. Review and revoke any account or access path tied to the embedded credential. Restrict network and administrative access until the vulnerable system is fixed or removed.
NIST SP 800-53 Rev 5	IA-5 — Authenticator Management	The flaw centers on embedded credentials that must be rotated or invalidated.
	AC-6 — Least Privilege	Reducing blast radius matters if the product remained reachable before remediation.
Recommendation — Rotate, revoke, or replace the exposed authenticator and any dependent sessions. Limit the vulnerable service to the minimum access needed while remediation is pending.

Practitioner Guidance

What to prioritise: Patch the product first where possible, but if patching is delayed, prioritize exposure removal over detective work. For this vulnerability class, an internet-exposed instance with a known hard-coded credential deserves immediate containment.

What to verify: Confirm that the fix actually removed the vulnerable access path, not just the visible symptom. Then verify credential rotation, session invalidation, and log review on any system that may have shared the same secret or trust boundary.

Practitioner takeaway: Treat hard-coded credential vulnerabilities as both a patching problem and a credential compromise problem, because the technical fix is incomplete until you have reduced exposure and checked for prior abuse.