Is CVE-2017-0059 (Microsoft Internet Explorer Information Disclosure) being exploited in the wild?

Yes. CISA added CVE-2017-0059 to its Known Exploited Vulnerabilities catalogue on 28 March 2022, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. Microsoft Internet Explorer allow remote attackers to obtain sensitive information from process memory via a crafted web site. Any organisation running the affected product should treat remediation as urgent.

What makes this CVE a live exploitation concern?

The practical question is not whether the flaw exists, but whether attackers are already using it. For CVE-2017-0059, the answer is yes, and that means exposure should be handled as an active security problem rather than a historical software defect. A browser flaw with confirmed exploitation can be used opportunistically wherever the affected product is still present and reachable by users.

That matters because browser exploitation often needs little more than a crafted website or lured user interaction. When a vulnerability is already in the wild, defenders should assume exposure can exist anywhere the product remains installed, enabled, or reachable through legacy workflows, even if no alert has yet appeared.

For exploitation-driven triage, keep the focus on whether the vulnerable browser is still in use, whether it is reachable from user workstations, and whether users have alternate browsers or hardened browsing paths. If you need a broader response model for exploited issues, the Zero-Day and Exploited Vulnerabilities Guide is useful for emergency triage, mitigation, and post-patch hunting.

What should you confirm before treating the issue as contained?

First confirm where the affected product is still installed and whether it is still used for browsing, embedded application access, or legacy compatibility. In many environments the risk is not a single desktop, but a long tail of unmanaged endpoints, older images, application dependencies, and fallback workflows that keep the vulnerable browser alive.

Next verify whether the vulnerable browser has been disabled, isolated, or removed from normal user paths. If the product still exists on a host, the absence of a visible incident does not mean the exposure is gone. You should also check whether browser hardening, extension control, and managed browser policy reduce the likelihood that users can be driven into a malicious page or follow-on compromise. NHIMG’s Enterprise Browser and Browser Security Guide is a useful companion when the real problem is browser exposure rather than one isolated CVE.

Because the direct answer depends on active exploitation rather than theoretical impact, authoritative confirmation should come from the vendor advisory and the CISA KEV catalogue, not from version folklore or stale scanning assumptions. For recordkeeping and validation, the CVE Program, the NIST National Vulnerability Database, and the CISA Known Exploited Vulnerabilities Catalog are the right references to check.

How should remediation and post-exposure review be handled?

For exploited browser flaws, the decision tree is simple: remove the exposure first, then review for signs of compromise. If immediate patching or removal is not possible, isolate affected systems from unnecessary browsing, tighten allowed browsing paths, and reduce the chance that a malicious site can be reached from privileged or sensitive sessions.

After remediation, assess whether the vulnerable browser may have been used to disclose memory contents or other sensitive information. That can justify credential rotation, session invalidation, or token review where browser-stored secrets, authenticated sessions, or sensitive application access may have been exposed. Treat this as a blast-radius question, not just a patching task.

In practice, organisations do best when they combine vulnerability response with browser governance and asset inventory. Vulnerability Management Guide helps frame KEV-driven prioritisation, while a browser-specific review avoids the common mistake of declaring success once patching is scheduled.

Risk and Threat Considerations

Active exploitation changes the risk profile from hypothetical to operational. A browser information-disclosure flaw can be abused to steal sensitive memory contents from a user session, which may expose credentials, tokens, or other data that can be reused for follow-on access.

Failure mechanism: An attacker lures a user to a crafted website, triggers the vulnerability in the browser process, and extracts sensitive information from memory before the victim realises anything happened.

Impact: The immediate impact is potential disclosure of confidential session data, but the downstream impact can be broader if the exposed information supports account takeover, lateral movement, or secondary compromise of connected services.

Standards & Framework Alignment

This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.

CIS Controls v8, NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.

Framework	Control / Reference	Relevance
CIS Controls v8	CIS-7 — Continuous Vulnerability Management	Active exploitation requires rapid identification and remediation of vulnerable assets.
Recommendation — Prioritise KEV-listed vulnerabilities for immediate remediation and verify affected asset coverage.
NIST SP 800-53 Rev 5	SI-2 — Flaw Remediation	The answer hinges on urgent remediation of an actively exploited software flaw.
	RA-5 — Vulnerability Monitoring and Scanning	Confirming exposure depends on discovering where the vulnerable browser remains installed.
Recommendation — Apply flaw remediation promptly and document emergency exception handling until closure. Scan for the affected product and validate remediation status across the asset estate.
NIST CSF 2.0	ID.RA-01 — Asset vulnerabilities are identified and documented	The question depends on identifying the vulnerable product and confirming exposure.
	RS.MA-1 — Responses to detected events are managed	Confirmed exploitation requires a managed response, not just patch scheduling.
Recommendation — Identify the vulnerable browser on in-scope assets and document exposure for prioritisation. Activate a managed response workflow for confirmed exploitation and track closure to evidence.

Practitioner Guidance

What to prioritise: Treat confirmed in-the-wild exploitation as a containment and exposure problem first. If the affected browser is still present, remove or disable it from normal use before you spend time debating whether the vulnerability is “old.”

What to verify: Confirm whether any user session, browser cache, saved credentials, or adjacent application access could have been exposed on hosts that were reachable during the exploitation window. If you cannot rule that out, assume the blast radius may extend beyond the browser itself.

Decision rule: If the system can still browse untrusted content with the vulnerable product, the environment is not yet safe enough to defer action. If the browser has already been remediated, move immediately to compromise review and credential hygiene rather than stopping at patch closure.

Practitioner takeaway: When CISA marks a browser CVE as actively exploited, the question becomes whether you can still contain the exposure and preserve trust in any sessions or secrets that may have passed through it.