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Threats / Microsoft / CVE-2023-28252
CVE-2023-28252 · EUVD no mirror located · GCVE no mirror located Verified 2026-06-22

Microsoft Windows vulnerability

Microsoft Windows Common Log File System (CLFS) driver vulnerability allows privilege escalation. Actively exploited in ransomware campaigns.

Verdict

Today item, not a backlog item.

A privilege escalation flaw in the Windows CLFS driver enables attackers to elevate permissions from lower-privileged contexts. Active exploitation in ransomware operations demonstrates immediate threat to Windows systems.

CISA KEV Yes · 2023-04-113Ransomware use Flagged3EPSS 0.48973 (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
25 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 2023-04-11), flagged for known ransomware use.
CISA KEV ↗Confirmed
Probability (EPSS)
EPSS 0.48973 — 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.
NVD ↗Reported
Weakness (CWE)
Mapped to CWE-122 Heap-based Buffer Overflow — weakness family: Memory safety.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
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
Execute code in a low-privilege process context on a target Windows system.
Business
Initial compromise foothold established with limited permissions.
2

Keys to the kingdom — privilege/identity takeover narrative 2

Attacker
Trigger the CLFS driver vulnerability to escalate privileges to system or administrator level.
Business
Attacker gains unrestricted control over the compromised host.
3

Lateral reach — past segmentation narrative 3

Attacker
Deploy ransomware payload with elevated privileges across the system and network.
Business
Critical data encrypted, operations disrupted, ransom demanded.
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)
  • Ransomware-use flag (CISA)
  • EPSS probability (FIRST)
  • Public PoC available (VulnCheck)
  • 25 reported-exploitation source(s)
  • CWE weakness mapping (NVD)
  • 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.