Threats / Cisco / CVE-2020-3153
CVE-2020-3153
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-09-19
Cisco AnyConnect Secure vulnerability
Cisco AnyConnect Secure Mobility Client for Windows improperly handles directory paths, allowing authenticated attackers to write malicious files to arbitrary locations with system privileges via DLL hijacking or preloading.
Verdict
Today item, not a backlog item.
An authenticated attacker on Windows can exploit improper path handling in AnyConnect to place malicious files in system-privileged locations, enabling privilege escalation and code execution. This vulnerability has been exploited in ransomware campaigns.
CISA KEV Yes · 2022-10-245Ransomware use Flagged5EPSS 0.28307 (verify live)6Exploit Public PoC7CVSS 6.53CISA SSVC Exploitation: active · Automatable: no · Impact: partial4
01
Is it exploitable?
— the evidence, ranked above the scoreExploit 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
2 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 2022-10-24), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.28307 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 6.5 (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N) · Affected: Cisco, AnyConnect Secure. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.0, set at disclosure.
Weakness (CWE)
Mapped to CWE-427 Uncontrolled Search Path.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: partialCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 978 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
Public exploit available
Public exploit tooling is catalogued for this CVE (a functional/weaponized public exploit). Catalog entries: Metasploit module. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
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 obtain valid Windows credentials through phishing, credential stuffing, or insider access.
Business
Attacker gains foothold with user-level access to a Windows endpoint running AnyConnect.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a malicious DLL and exploit the path-handling flaw to write it to a directory where AnyConnect or Windows processes search for libraries.
Business
Malicious code is positioned in a trusted system location, bypassing application-level security controls.
3
Lateral reach — past segmentation narrative 3
Attacker
I trigger DLL loading through normal AnyConnect operation or system process execution, causing the malicious library to load with system privileges.
Business
Attacker achieves privilege escalation and arbitrary code execution in the system context.
4
Data at risk — exfiltration narrative 4
Attacker
I deploy ransomware, backdoors, or lateral movement tools with full system access.
Business
Organization suffers data encryption, exfiltration, or compromise of network infrastructure.
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’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by ciscoCNA
Credited with finding itYorick Koster, working with the SSD Secure Disclosure programfinder
Found an error? Propose a correction.
A correction is a cited counter-claim — it must cite a source,
gets reviewed by a second human, and is never auto-applied. See the
correction convention and our identity
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