CVE-2023-27997UnknownPublished 9 Feb 2026

tlp clear · KRVTZ-NET IDS alerts for 2026-02-09

Affects tlp clearSource CIRCL OSINT Feed

TLP:CLEAR, disclosure is not limited

Authoritative record:CVE-2023-27997· Critical 9.2

Exploited in the wild · used in ransomware campaigns · KEV due 4 Jul 2023 · 85% EPSS : block it and hunt for it in your logs now.

Data as of 26 Oct 2026, 09:15 UTC

CVSS 3.1 base score

9.2Critical

How severe the flaw is on the 0–10 CVSS scale.

KEV deadline: 4 Jul 2023 US federal agencies must patch by this date; a sensible deadline for everyone else.
Ransomware: Used in ransomware campaigns
EPSS: 85.6% chance of exploitation in 30 days – higher than 99% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:X/RC:R

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 13 Jun 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV the same day as disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by Fortinet, Inc.
9 Mar 202310:09 UTC, 96 days before disclosure
CVE published
on cve.org
13 Jun 202308:41 UTC, t = 0
Added to CISA KEV (opens in a new tab)
exploitation confirmed · ransomware use known
13 Jun 2023, the same day as disclosure
KEV remediation due
US federal deadline
4 Jul 2023, 21 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Apply updates per vendor instructions.

Description

The KRVTZ-NET IDS alerts from February 9, 2026, report reconnaissance and scanning activities targeting network infrastructure, especially Fortigate VPN devices and submission services. The activity includes brute force attempts from IP 152.32.151.39 and exploitation attempts of CVE-2023-27997 from IP 2001:470:1:332::148. Some attackers use Google Webcrawler user-agent spoofing to evade detection. No active exploitation or ransomware campaigns are currently reported, but these reconnaissance actions could lead to more serious attacks. European organizations using Fortigate VPNs are particularly at risk. The threat is assessed as low severity but could impact confidentiality and integrity if unmitigated. Recommended mitigations include proactive patching, enhanced monitoring, multi-factor authentication, and network segmentation.

Impact

The reconnaissance and scanning activities pose a risk to the confidentiality and integrity of targeted network infrastructure, particularly Fortigate VPN devices. Exploitation of CVE-2023-27997 could allow unauthorized access or compromise of VPN services. Although no active exploitation or ransomware campaigns are currently reported, the presence of known exploits in the wild and known ransomware campaign use indicates a credible threat. If successful, attacks could lead to unauthorized access, data breaches, or disruption of services.

Defensive guidance

Organizations should proactively apply any vendor updates once released. Meanwhile, implement enhanced network monitoring to detect suspicious activities such as brute force attempts and unusual login requests. Employ multi-factor authentication (MFA) on VPN access to reduce risk from credential-based attacks. Network segmentation can limit the impact of a potential compromise. Follow vendor advisories and update defenses accordingly.

Summary

This threat report details reconnaissance and scanning activities detected by KRVTZ-NET IDS on February 9, 2026, focusing on Fortigate VPN devices and submission services. Indicators include repeated brute force connection attempts from IP 152.32.151.39 and repeated GET requests to the /remote/logincheck endpoint from IP 2001:470:1:332::148, exploiting CVE-2023-27997. Attackers also use Google Webcrawler user-agent spoofing to avoid detection. While no active exploitation or ransomware campaigns are currently observed, these early-stage activities represent potential precursors to more severe attacks. The vulnerability CVE-2023-27997 is known to be exploited in the wild and is listed in the CISA KEV catalog. The threat is particularly relevant to European organizations using Fortigate VPNs.

CWE-122Heap-based Buffer Overflow (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #16
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
Pre-design: Use a language or compiler that performs automatic bounds checking.
Architecture and Design
Use an abstraction library to abstract away risky APIs. Not a complete solution.
Operation · Build and Compilation · Environment Hardening
Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Forced Integer Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

Indicators of compromise

IP addresses 5

152.32.151.39haproxy: 152.32.151.39 connecting to (submission/TCP) 15x in hour, possible bruteforcing.
2001:470:1:332::148ET EXPLOIT Fortigate VPN - Repeated GET Requests to /remote/logincheck (CVE-2023-27997)
165.165.120.46ET SCAN Google Webcrawler User-Agent (Mediapartners-Google)
14.176.76.54ET SCAN Google Webcrawler User-Agent (Mediapartners-Google)
14.244.210.136ET SCAN Google Webcrawler User-Agent (Mediapartners-Google)

Community reviews

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Exploitation evidence

Timeline

What to do

Description

AI analysisMachine-generated, updated 25 Oct 2026, 21:15 UTC

WeaknessesCWE-122

Indicators of compromise

IP addresses 5

Community reviews

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