CVE-2023-35698Network attack vector

FTP username disclosure via distinguishable login failures

Published Jul 10, 2023 · Updated Jun 1, 2026

Observable response discrepancy in SICK AG ICR890-4 firmware before 2.5.0 allows remote attackers to identify valid FTP usernames. The FTP authentication path returns distinguishable responses for failed logins depending on whether the submitted username is valid. No authentication or user interaction is required; disclosed account names can support targeted password guessing, but the flaw does not disclose passwords.

CVSS severity5.3
Medium
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable response discrepancy in SICK AG ICR890-4 firmware before 2.5.0 allows remote attackers to identify valid FTP usernames. The FTP authentication path returns distinguishable responses for failed logins depending on whether the submitted username is valid. No authentication or user interaction is required; disclosed account names can support targeted password guessing, but the flaw does not disclose passwords.

The record

CVE
CVE-2023-35698
Published
Jul 10, 2023
Updated
Jun 1, 2026
Vendor
SICK AG
Product
ICR890-4
Classifications
CWE-204, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 10, 2023CVE publishedPublication date reported by the CVE source.
  2. Jun 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.5.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SICK AG · ICR890-4version=0 <2.5.0

Published CVSS scores

5.3SICK AGCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3NISTCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-204Observable Response Discrepancy
T1087Account Discovery

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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