CVE-2021-33540Network attack vector

Monitoring-data disclosure via hard-coded FTP password

Published Jun 25, 2021 · Updated Sep 17, 2024

Hard-coded credentials in Phoenix Contact AXL F BK and IL BK devices allow remote attackers to read monitoring data through FTP. An undocumented FTP service accepts an embedded password and exposes the device root directory, including scrambled monitoring information. Exploitation requires obtaining that password and network access to the FTP service; the vendor documents reading the monitoring data as the concrete consequence.

CVSS severity7.3
High
EPSS probability0.72%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Hard-coded credentials in Phoenix Contact AXL F BK and IL BK devices allow remote attackers to read monitoring data through FTP. An undocumented FTP service accepts an embedded password and exposes the device root directory, including scrambled monitoring information. Exploitation requires obtaining that password and network access to the FTP service; the vendor documents reading the monitoring data as the concrete consequence.

The record

CVE
CVE-2021-33540
Published
Jun 25, 2021
Updated
Sep 17, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-798, T0859
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.3CERT@VDECVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
7.3Phoenix ContactCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
T0859Valid Accounts

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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