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CVE-2023-34758

Silver vulnerable to MitM attack against implants due to a cryptography vulnerability

8.1 HighFix available

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.59%Up 0.5 points since Aug 29, 2023
90%50%10%1%

What each source reports

NVD Score used 8.1

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Record
CVE-2023-34758
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-327
Updated
2026-11-02
CVE List No score

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Record
CVE-2023-34758
Updated
2026-11-02
EUVDEUVD-2023-1750 No score

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Record
EUVD-2023-1750
Updated
2026-11-03
GitHub AdvisoriesGHSA-8jxm-xp43-qh3q 9.2

Silver vulnerable to MitM attack against implants due to a cryptography vulnerability

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.

Record
GHSA-8jxm-xp43-qh3q
CVSS 4.0
9.2 CriticalCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-327
Updated
2026-11-02
OSVGHSA-8jxm-xp43-qh3q 9.2

Silver vulnerable to MitM attack against implants due to a cryptography vulnerability

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.

Record
GHSA-8jxm-xp43-qh3q
CVSS 4.0
9.2 CriticalCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.1 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-327
Updated
2026-11-02
OSV No score

Sliver from v1.5.x to v1.5.39 has an improper cryptographic implementation, which allows attackers to execute a man-in-the-middle attack via intercepted and crafted responses.

Record
CVE-2023-34758
Updated
2026-11-02
OSVGO-2023-1866 No score

Silver vulnerable to MitM attack against implants due to a cryptography vulnerability in github.com/bishopfox/sliver

Silver vulnerable to MitM attack against implants due to a cryptography vulnerability in github.com/bishopfox/sliver

Record
GO-2023-1866
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
github.com/bishopfox/sliver
Go
1.5.0 up to 1.5.40
1.5.40
github.com/bishopfox/sliver
Go
From an advisory covering 2 CVEs
1.5.0 up to 1.5.40
1.5.40

History

History
RecordedChangedSources
affected, facts
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2023-34758 is a high vulnerability (CVSS 8.1) in Bishopfox Sliver, published June 21, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.59%, the 48th percentile. Fixed in github.com/bishopfox/sliver 1.5.40.

References

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