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Threats / Microsoft / CVE-2017-8570
CVE-2017-8570 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Office vulnerability

Microsoft Office remote code execution vulnerability caused by improper memory object handling. Actively exploited in the wild with high EPSS score.

Verdict

Today item — known-exploited.

A memory corruption flaw in Microsoft Office allows unauthenticated remote attackers to execute arbitrary code by crafting malicious documents. Active exploitation in the wild indicates immediate risk to organizations using affected Office versions.

CISA KEV Yes · 2022-02-253EPSS 0.89889 (verify live)4Exploit Public PoC5
01

Is it exploitable?

— the evidence, ranked above the score
Exploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
16 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-02-25).
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.89889 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Office. Confirm exact fixed builds in the vendor advisory.
NVD ↗Reported
02

Who’s exploiting it?

— attribution turns risk into urgency
Attribution not established

No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.

03

Why it matters

— the attack path, told twice: adversary, then board
1

Front door — unauthenticated access narrative 1

Attacker
I craft a malicious Office document containing specially formatted objects designed to trigger memory corruption when processed.
Business
End users receive seemingly legitimate Office files via email or download that silently execute attacker code upon opening.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
I deliver the weaponized document through phishing, watering hole, or direct distribution to target systems running vulnerable Office software.
Business
Widespread infection risk across the organization as employees routinely open Office documents in normal business workflows.
3

Lateral reach — past segmentation narrative 3

Attacker
I gain code execution in the context of the user opening the document, establishing initial system compromise.
Business
Attackers obtain foothold for lateral movement, data exfiltration, or persistent backdoor installation within corporate networks.
04

What to do

— defensible action
  • Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05

Coverage & confidence

— what we know, and what we don’t

Established (cited)

  • KEV listing (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 16 reported-exploitation source(s)
  • Public exploit availability
  • Catalogued by microsoft (CNA)
  • Coverage gaps — stated, not hidden

  • No EUVD / GCVE mirror in feed — single-authority dependency for the identifier.
  • EPSS & exposure are time-varying; verify live at the source.
  • Threat-actor attribution not established from feed data — absence of a name is not absence of compromise.
  • No finder/reporter credit recorded in the public CVE entry — the work behind this find is unattributed.
  • Disclosure & credit2
    Catalogued by microsoftCNA
    Credited with finding itNo finder named in the public CVE record — the work behind this find is unattributed.