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CVE-2023-4966 KEVRansomwarePublic exploit High · 7.5 EPSS >99.9%

Citrix NetScaler ADC and NetScaler Gateway Buffer Overflow Vulnerability

Citrix · NetScaler ADC and NetScaler Gateway

Summary

Citrix NetScaler ADC and NetScaler Gateway contain a buffer overflow vulnerability that affects deployments configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, or RDP Proxy) or as an AAA virtual server. Through this flaw, an attacker with network access can cause sensitive information to be disclosed, requiring no authentication, no privileges, and no user interaction.

Official description · NVD

Sensitive information disclosure in NetScaler ADC and NetScaler Gateway when configured as a Gateway (VPN virtual server, ICA Proxy, CVPN, RDP Proxy) or AAA  virtual server.

Breakdown
82.1 / 100
Exploited
Yes, in CISA KEV
Reports
1
Tactics
3/15

How an attack unfolds

Based on mappings. Select a step to see the evidence.
  1. How attackers get in

  2. What they do

First seen exploited 7 days after disclosure. Public exploit code (PoC-in-GitHub) appeared 14 days after disclosure.

  1. Disclosedday 0
  2. First seen exploitedVulnCheck KEV evidence+7 days
  3. Added to CISA KEVknown ransomware use; EU database agrees+8 days
  4. Public exploit codePoC-in-GitHub+14 days

CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.

techniques

2 , grouped by in kill-chain order 2

ExecutionTA0002

Hijack Execution Flow T1574 also Stealth
MITRE CTID mapping of the KEV entry · how it is exploited

This is a buffer overflow vulnerability that results in unauthorized disclosure of memory, including session tokens.

CollectionTA0009

MITRE CTID mapping of the KEV entry · primary impact

This is a buffer overflow vulnerability that results in unauthorized disclosure of memory, including session tokens.

Lower-confidence links (1)

These come from early or generic mappings, text matching, or contradict this CVE’s details (for example a public-facing technique on a bug that needs a user to open a file). Shown for completeness.

  • Token Impersonation/TheftT1134.001 Windows-only technique on a non-Windows product

Detection

4 rules for this CVE · 22 general rules for its techniques

Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.

What security researchers reported

Named in 1 threat report
1 reportGoogle Mandiant

Reports are matched by finding the exact id CVE-2023-4966 in their text; nobody has reviewed the match. One passage is shown per report, at most 320 characters, linked to the original.

Also mentioned in 50 community threat pulses (AlienVault OTX)

Weaker evidence

Pulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.

References

3 links, grouped by NVD tag (2 duplicates merged)
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