LiveActive security incident?Get immediate response
MITRE ATT&CK® Malware

S0487: Kessel

Kessel is an advanced version of OpenSSH which acts as a custom backdoor, mainly acting to steal credentials and function as a bot. Kessel has been active since its C2 domain began resolving in August 2018.[1]

EnterpriseS0487MalwareObject v1.1Modified
Discuss defensive coverageBack to ATT&CK
Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

S0487: Kessel describes [Kessel](https://attack.mitre.org/software/S0487) is an advanced version of OpenSSH which acts as a custom backdoor, mainly acting to steal credentials and function as a bot. [Kessel](https://attack.mitre.org/software/S0487) has been active since its C2 domain began resolving in August 2018.(Citation: ESET ForSSHe December 2018)

Executive priority

S0487: Kessel is an official MITRE ATT&CK software. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.

Technical view

Security teams should validate S0487: Kessel by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Linux), and available local telemetry before making detection or mitigation decisions.

Likely telemetry

  • Official ATT&CK relationships and object metadata
  • Network, endpoint, and security-tool telemetry

Detection direction

  • Validate whether S0487: Kessel appears in your detection coverage and tabletop scenarios.
  • Use the object to align executive risk language with SOC, incident response, and detection engineering work.
  • Do not treat ATT&CK relationship context as attribution without corroborating evidence.

Mitigation priorities

  • Map the object to existing controls and identify missing telemetry or response ownership.
  • Prioritize mitigations that reduce exposure on the listed platforms and tactics.
  • Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits

Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.

This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

Kessel

Kessel is an advanced version of OpenSSH which acts as a custom backdoor, mainly acting to steal credentials and function as a bot. Kessel has been active since its C2 domain began resolving in August 2018.[1]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

How security teams should use this page

Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.

ATT&CK relationship table

Techniques used

This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.

14 rows
DomainIDNameRelationship / procedure
EnterpriseT1027.013Encrypted/Encoded FileSub-technique

Kessel's configuration is hardcoded and RC4 encrypted within the binary.[1]

EnterpriseT1105Ingress Tool Transfer

Kessel can download additional modules from the C2 server.[1]

EnterpriseT1030Data Transfer Size Limits

Kessel can split the data to be exilftrated into chunks that will fit in subdomains of DNS queries.[1]

EnterpriseT1059Command and Scripting Interpreter

Kessel can create a reverse shell between the infected host and a specified system.[1]

EnterpriseT1140Deobfuscate/Decode Files or Information

Kessel has decrypted the binary's configuration once the main function was launched.[1]

EnterpriseT1016System Network Configuration Discovery

Kessel has collected the DNS address of the infected host.[1]

EnterpriseT1554Compromise Host Software Binary

Kessel has maliciously altered the OpenSSH binary on targeted systems to create a backdoor.[1]

EnterpriseT1082System Information Discovery

Kessel has collected the system architecture, OS version, and MAC address information.[1]

EnterpriseT1090Proxy

Kessel can use a proxy during exfiltration if set in the configuration.[1]

EnterpriseT1556Modify Authentication Process

Kessel has trojanized the ssh_login and user-auth_pubkey functions to steal plaintext credentials.[1]

EnterpriseT1132.001Standard EncodingSub-technique

Kessel has exfiltrated data via hexadecimal-encoded subdomain fields of DNS queries.[1]

EnterpriseT1560Archive Collected Data

Kessel can RC4-encrypt credentials before sending to the C2.[1]

EnterpriseT1041Exfiltration Over C2 Channel

Kessel has exfiltrated information gathered from the infected system to the C2 server.[1]

EnterpriseT1048.003Exfiltration Over Unencrypted Non-C2 ProtocolSub-technique

Kessel can exfiltrate credentials and other information via HTTP POST request, TCP, and DNS.[1]

Relationship explorer

All related ATT&CK context

uses · TechniqueT1027.013: Encrypted/Encoded FileEnterpriseuses · TechniqueT1105: Ingress Tool TransferEnterpriseuses · TechniqueT1030: Data Transfer Size LimitsEnterpriseuses · TechniqueT1059: Command and Scripting InterpreterEnterpriseuses · TechniqueT1140: Deobfuscate/Decode Files or InformationEnterpriseuses · TechniqueT1016: System Network Configuration DiscoveryEnterpriseuses · TechniqueT1554: Compromise Host Software BinaryEnterpriseuses · TechniqueT1082: System Information DiscoveryEnterpriseuses · TechniqueT1090: ProxyEnterpriseuses · TechniqueT1556: Modify Authentication ProcessEnterpriseuses · TechniqueT1132.001: Standard EncodingEnterpriseuses · TechniqueT1560: Archive Collected DataEnterpriseuses · TechniqueT1041: Exfiltration Over C2 ChannelEnterpriseuses · TechniqueT1048.003: Exfiltration Over Unencrypted Non-C2 ProtocolEnterprise
Change history

Object version and sync metadata

The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.

ATT&CK release
19.2
Object version
1.1
Created
Modified
Raw hash
5a68f7997ddbcef9...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.1Current bundle5a68f7997ddb…
19.11.1Older bundle5a68f7997ddb…
Raw source

Mirrored ATT&CK source object

The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.

Open mirrored raw JSONOpen MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    ESET ForSSHe December 2018

    Dumont, R., M.Léveillé, M., Porcher, H. (2018, December 1). THE DARK SIDE OF THE FORSSHE A landscape of OpenSSH backdoors. Retrieved July 16, 2020.

    Open source URL
  2. [2]
    mitre-attackS0487
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

Official MITRE ATT&CK siteOfficial STIX data repositoryMITRE ATT&CK terms of use