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MitM attack against implants due to a cryptographic vulnerability

High
moloch-- published GHSA-8jxm-xp43-qh3q Jun 20, 2023

Package

Sliver

Affected versions

1.5.0 - 1.5.39

Patched versions

1.5.40+

Description

Summary

The current cryptography implementation in Sliver up to version 1.5.39 allows a MitM with access to the corresponding implant binary to execute arbitrary codes on implanted devices via intercepted and crafted responses. (Reserved CVE ID: CVE-2023-34758)

Details

Please see the PoC repo.

PoC

Please also see the PoC repo.
To setup a simple PoC environment,

  1. Generate an implant with its C2 set to the PoC server's address and copy the embedded private implant key and public server key into the config json.
  2. Run the implant on a separate VM and a notepad.exe window should pop up on the implanted VM.

Impact

A successful attack grants the attacker permission to execute arbitrary code on the implanted device.

References

https://github.com/BishopFox/sliver/blob/master/implant/sliver/cryptography/implant.go
https://github.com/BishopFox/sliver/blob/master/implant/sliver/cryptography/crypto.go
https://github.com/tangent65536/Slivjacker

Credits

Ting-Wei Hsieh from CHT Security Co. Ltd.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVE ID

CVE-2023-35170

Weaknesses

No CWEs