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Hashicorp Vault plugin for authenticating Trusted Execution Environments (TEE) like SGX enclaves
![]() [](https://renovatebot.com) This PR contains the following updates: | Package | Change | Age | Adoption | Passing | Confidence | |---|---|---|---|---|---| | golang.org/x/crypto | `v0.16.0` -> `v0.17.0` | [](https://docs.renovatebot.com/merge-confidence/) | [](https://docs.renovatebot.com/merge-confidence/) | [](https://docs.renovatebot.com/merge-confidence/) | [](https://docs.renovatebot.com/merge-confidence/) | ### GitHub Vulnerability Alerts #### [CVE-2023-48795](https://togithub.com/warp-tech/russh/security/advisories/GHSA-45x7-px36-x8w8) ### Summary Terrapin is a prefix truncation attack targeting the SSH protocol. More precisely, Terrapin breaks the integrity of SSH's secure channel. By carefully adjusting the sequence numbers during the handshake, an attacker can remove an arbitrary amount of messages sent by the client or server at the beginning of the secure channel without the client or server noticing it. ### Mitigations To mitigate this protocol vulnerability, OpenSSH suggested a so-called "strict kex" which alters the SSH handshake to ensure a Man-in-the-Middle attacker cannot introduce unauthenticated messages as well as convey sequence number manipulation across handshakes. **Warning: To take effect, both the client and server must support this countermeasure.** As a stop-gap measure, peers may also (temporarily) disable the affected algorithms and use unaffected alternatives like AES-GCM instead until patches are available. ### Details The SSH specifications of ChaCha20-Poly1305 (chacha20-poly1305@​openssh.com) and Encrypt-then-MAC (*-etm@openssh.com MACs) are vulnerable against an arbitrary prefix truncation attack (a.k.a. Terrapin attack). This allows for an extension negotiation downgrade by stripping the SSH_MSG_EXT_INFO sent after the first message after SSH_MSG_NEWKEYS, downgrading security, and disabling attack countermeasures in some versions of OpenSSH. When targeting Encrypt-then-MAC, this attack requires the use of a CBC cipher to be practically exploitable due to the internal workings of the cipher mode. Additionally, this novel attack technique can be used to exploit previously unexploitable implementation flaws in a Man-in-the-Middle scenario. The attack works by an attacker injecting an arbitrary number of SSH_MSG_IGNORE messages during the initial key exchange and consequently removing the same number of messages just after the initial key exchange has concluded. This is possible due to missing authentication of the excess SSH_MSG_IGNORE messages and the fact that the implicit sequence numbers used within the SSH protocol are only checked after the initial key exchange. In the case of ChaCha20-Poly1305, the attack is guaranteed to work on every connection as this cipher does not maintain an internal state other than the message's sequence number. In the case of Encrypt-Then-MAC, practical exploitation requires the use of a CBC cipher; while theoretical integrity is broken for all ciphers when using this mode, message processing will fail at the application layer for CTR and stream ciphers. For more details see [https://terrapin-attack.com](https://terrapin-attack.com). ### Impact This attack targets the specification of ChaCha20-Poly1305 (chacha20-poly1305@​openssh.com) and Encrypt-then-MAC (*-etm@openssh.com), which are widely adopted by well-known SSH implementations and can be considered de-facto standard. These algorithms can be practically exploited; however, in the case of Encrypt-Then-MAC, we additionally require the use of a CBC cipher. As a consequence, this attack works against all well-behaving SSH implementations supporting either of those algorithms and can be used to downgrade (but not fully strip) connection security in case SSH extension negotiation (RFC8308) is supported. The attack may also enable attackers to exploit certain implementation flaws in a man-in-the-middle (MitM) scenario. --- ### Configuration 📅 **Schedule**: Branch creation - "" (UTC), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate](https://www.mend.io/free-developer-tools/renovate/). View repository job log [here](https://developer.mend.io/github/matter-labs/vault-auth-tee). <!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy45My4xIiwidXBkYXRlZEluVmVyIjoiMzcuMTAzLjEiLCJ0YXJnZXRCcmFuY2giOiJtYWluIn0=--> Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com> |
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SECURITY.md |
vault-auth-tee
TEE remote attestation plugin for Hashicorp Vault
⚠️☢️☣️ WARNING: not yet for production use ☣️☢️⚠️
License
All of the code is licensed under the Mozilla Public License 2.0 unless otherwise specified.
Most of the vault plugin code is based on the vault builtin/credential/cert
plugin.
Build Setup
$ wget -qO - https://download.01.org/intel-sgx/sgx_repo/ubuntu/intel-sgx-deb.key | sudo apt-key add -
$ sudo bash -c 'echo "deb [arch=amd64] https://download.01.org/intel-sgx/sgx_repo/ubuntu focal main" > /etc/apt/sources.list.d/intel-sgx.list'
$ sudo apt update
$ sudo apt install -y --no-install-recommends \
libsgx-headers \
libsgx-enclave-common \
libsgx-urts \
libsgx-dcap-quote-verify \
libsgx-dcap-quote-verify-dev
Configuration
Create
or Update
via the ${plugin}/tees/$name
endpoint
{
"name": "TEE_role_name",
"token_policies": "policy1,policy2,...",
"types": "sgx",
"sgx_mrsigner": "298037d88782e022e019b3020745b78aa40ed95c77da4bf7f3253d3a44c4fd7e",
"sgx_mrenclave": "18946b3547d3ca036f4df7b516857e28fd512d69fed3411dc660537912faabf8",
"sgx_isv_prodid": 0,
"sgx_min_isv_svn": 0,
"sgx_allowed_tcb_levels": "Ok,ConfigNeeded,OutOfDate,OutOfDateConfigNeeded,SwHardeningNeeded,ConfigAndSwHardeningNeeded"
}
- At least one of
sgx_mrsigner
orsgx_mrenclave
must be set. If both are set, both are used for matching. sgx_isv_prodid
is optional and defaults to0
.sgx_min_isv_svn
is optional and defaults to0
.sgx_allowed_tcb_levels
is optional and defaults toOk
.
Authentication
- Client TEE generates a self-signed TLS client certificate
- Client TEE generates an attestation report, which includes the hash of the public key of the client certificate (in case of SGX, a sha256 sum of the public key)
- Client TEE fetches all collateral material via e.g. Intel DCAP (
tee_qv_get_collateral
) - Client TEE sends POST request with a TLS connection using the client certificate
to Vault via the
${plugin}/login
endpoint with the name, attestation report and the attestation collateral material - An optional challenge can be included in the POST request, which is then included in the attestation report of the vault response
{
"name": "The name of the TEE role to authenticate against.",
"quote": "The quote Base64 encoded.",
"collateral": "The collateral Json string encoded.",
"challenge": "An optional challenge hex encoded."
}
The response contains the Vault token and, if a challenge was included, the vault attestation report, which must contain the challenge bytes in the report_data of the quote.
{
"auth": {
"client_token": "The Vault token.",
"....": "...."
},
"data": {
"quote": "The vault quote Base64 encoded.",
"collateral": "The vault collateral Json string encoded."
}
}
Collateral Json encoding
{
"major_version": uint16,
"minor_version": uint16,
"tee_type": uint32,
"pck_crl_issuer_chain": []byte,
"root_ca_crl": []byte,
"pck_crl": []byte,
"tcb_info_issuer_chain": []byte,
"tcb_info": []byte,
"qe_identity_issuer_chain": []byte,
"qe_identity": []byte
}