CVE-2024-55560Network attack vector

SSH server impersonation via persistent default host keys

Published Dec 8, 2024 · Updated Dec 9, 2024

Cryptographic key reuse in MailCleaner before 28d913e allows remote attackers to impersonate its SSH service using shipped host keys. Installation leaves identical private keys at /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key, and /etc/ssh/ssh_host_ed25519_key instead of generating unique host keys. Exploitation requires redirecting or intercepting an SSH connection; a client that trusts the shared host key can be connected to an attacker-controlled service.

CVSS severity9.8
Critical
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cryptographic key reuse in MailCleaner before 28d913e allows remote attackers to impersonate its SSH service using shipped host keys. Installation leaves identical private keys at /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key, and /etc/ssh/ssh_host_ed25519_key instead of generating unique host keys. Exploitation requires redirecting or intercepting an SSH connection; a client that trusts the shared host key can be connected to an attacker-controlled service.

The record

CVE
CVE-2024-55560
Published
Dec 8, 2024
Updated
Dec 9, 2024
Vendor
MailCleaner
Product
MailCleaner
Classifications
T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 8, 2024CVE publishedPublication date reported by the CVE source.
  2. Dec 9, 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?

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

  1. Affected versionversion=0 <28d913e

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

MailCleaner · MailCleanerversion=0 <28d913e

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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 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

T1557Adversary-in-the-Middle

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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