Threats / Microsoft / CVE-2017-0143
CVE-2017-0143
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Microsoft Windows vulnerability
Microsoft Windows SMBv1 contains an unspecified vulnerability enabling remote code execution. The flaw has been actively exploited in ransomware campaigns.
Verdict
Today item, not a backlog item.
Critical remote code execution vulnerability in SMBv1 protocol affecting Windows systems. High EPSS score and confirmed exploitation in ransomware operations indicate immediate threat to unpatched infrastructure.
CISA KEV Yes · 2021-11-033Ransomware use Flagged3EPSS 0.93307 (verify live)4Exploit Weaponized · public PoC5
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
21 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 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.93307 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Microsoft, Windows. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution 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 board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious SMB packet targeting the unspecified vulnerability in SMBv1 to trigger remote code execution on the target Windows system.
Business
Attacker gains arbitrary code execution on Windows servers and workstations, enabling lateral movement and persistence within the network.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I deploy ransomware payload across compromised systems to encrypt critical business data and demand ransom payment.
Business
Operations halt as files become inaccessible; business faces data loss, downtime, extortion demands, and potential regulatory penalties.
3
Lateral reach — past segmentation narrative 3
Attacker
I propagate the exploit worm-like across the network to maximize infection scope without requiring user interaction.
Business
Entire infrastructure becomes compromised rapidly; recovery costs escalate and incident response becomes exponentially more complex.
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