GHSA-F4R5-Q63F-GCWW
Vulnerability from github – Published: 2023-09-06 13:49 – Updated: 2024-09-27 21:25Impact
A security issue was found in the Keylime registrar code which allows an attacker to effectively bypass the challenge-response protocol used to verify that an agent has indeed access to an AIK which in indeed related to the EK.
When an agent starts up, it will contact a registrar and provide a public EK and public AIK, in addition to the EK Certificate. This registrar will then challenge the agent to decrypt a challenge encrypted with the EK.
When receiving the wrong "auth_tag" back from the agent during activation, the registrar answers with an error message that contains the expected correct "auth_tag" (an HMAC which is calculated within the registrar for checking). An attacker could simply record the correct expected "auth_tag" from the HTTP error message and perform the activate call again with the correct expected "auth_tag" for the agent.
The security issue allows an attacker to pass the challenge-response protocol during registration with (almost) arbitrary registration data. In particular, the attacker can provide a valid EK Certificate and EK, which passes verification by the tenant (or registrar), while using a compromised AIK, which is stored unprotected outside the TPM and is unrelated to former two. The attacker then deliberately fails the initial activation call to get to know the correct "auth_tag" and then provides it in a subsequent activation call. This results in an agent which is (incorrectly) registered with a valid EK Certificate, but with a compromised/unrelated AIK.
Patches
Users should upgrade to release 7.5.0
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "keylime"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "7.5.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2023-38201"
],
"database_specific": {
"cwe_ids": [
"CWE-639"
],
"github_reviewed": true,
"github_reviewed_at": "2023-09-06T13:49:43Z",
"nvd_published_at": "2023-08-25T17:15:08Z",
"severity": "HIGH"
},
"details": "### Impact\n\nA security issue was found in the Keylime `registrar` code which allows an attacker to effectively bypass the challenge-response protocol used to verify that an `agent` has indeed access to an AIK which in indeed related to the EK.\n\nWhen an `agent` starts up, it will contact a `registrar` and provide a public EK and public AIK, in addition to the EK Certificate. This `registrar` will then challenge the `agent` to decrypt a challenge encrypted with the EK. \n\nWhen receiving the wrong \"auth_tag\" back from the `agent` during activation, the `registrar` answers with an error message that contains the expected correct \"auth_tag\" (an HMAC which is calculated within the `registrar` for checking). An attacker could simply record the correct expected \"auth_tag\" from the HTTP error message and perform the activate call again with the correct expected \"auth_tag\" for the `agent`.\n\nThe security issue allows an attacker to pass the challenge-response protocol during registration with (almost) arbitrary registration data. In particular, the attacker can provide a valid EK Certificate and EK, which passes verification by the `tenant` (or `registrar`), while using a compromised AIK, which is stored unprotected outside the TPM and is unrelated to former two. The attacker then deliberately fails the initial activation call to get to know the correct \"auth_tag\" and then provides it in a subsequent activation call. This results in an `agent` which is (incorrectly) registered with a valid EK Certificate, but with a compromised/unrelated AIK.\n\n### Patches\nUsers should upgrade to release 7.5.0",
"id": "GHSA-f4r5-q63f-gcww",
"modified": "2024-09-27T21:25:28Z",
"published": "2023-09-06T13:49:43Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/keylime/keylime/security/advisories/GHSA-f4r5-q63f-gcww"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-38201"
},
{
"type": "WEB",
"url": "https://github.com/keylime/keylime/commit/9e5ac9f25cd400b16d5969f531cee28290543f2a"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2023:5080"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2023-38201"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2222693"
},
{
"type": "PACKAGE",
"url": "https://github.com/keylime/keylime"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/keylime/PYSEC-2023-160.yaml"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZIZZB5NHNCS5D2AEH3ZAO6OQC72IK7WS"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Keylime registrar and (untrusted) Agent can be bypassed by an attacker"
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.