CVE-2023-43635
EVE OS SHA1-Sealed Key Vault
Description
Vault Key Sealed With SHA1 PCRs The measured boot solution implemented in EVE OS leans on a PCR locking mechanism. Different parts of the system update different PCR values in the TPM, resulting in a unique value for each PCR entry. These PCRs are then used in order to seal/unseal a key from the TPM which is used to encrypt/decrypt the “vault” directory. This “vault” directory is the most sensitive point in the system and as such, its content should be protected. This mechanism is noted in Zededa’s documentation as the “measured boot” mechanism, designed to protect said “vault”. The code that’s responsible for generating and fetching the key from the TPM assumes that SHA256 PCRs are used in order to seal/unseal the key, and as such their presence is being checked. The issue here is that the key is not sealed using SHA256 PCRs, but using SHA1 PCRs. This leads to several issues: • Machines that have their SHA256 PCRs enabled but SHA1 PCRs disabled, as well as not sealing their keys at all, meaning the “vault” is not protected from an attacker. • SHA1 is considered insecure and reduces the complexity level required to unseal the key in machines which have their SHA1 PCRs enabled. An attacker can very easily retrieve the contents of the “vault”, which will effectively render the “measured boot” mechanism meaningless.
INFO
Published Date :
Sept. 20, 2023, 3:15 p.m.
Last Modified :
Sept. 28, 2023, 6:15 a.m.
Source :
[email protected]
Remotely Exploitable :
No
Impact Score :
6.0
Exploitability Score :
2.0
Affected Products
The following products are affected by CVE-2023-43635
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2023-43635.
| URL | Resource |
|---|---|
| https://asrg.io/security-advisories/cve-2023-43635/ |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2023-43635 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2023-43635 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Sep. 28, 2023
Action Type Old Value New Value Removed Reference https://asrg.io/security-advisories/vault-key-sealed-with-sha1-pcrs/ [Third Party Advisory] Added Reference https://asrg.io/security-advisories/cve-2023-43635/ [No Types Assigned] -
Initial Analysis by [email protected]
Sep. 25, 2023
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Changed Reference Type https://asrg.io/security-advisories/vault-key-sealed-with-sha1-pcrs/ No Types Assigned https://asrg.io/security-advisories/vault-key-sealed-with-sha1-pcrs/ Third Party Advisory Added CWE NIST CWE-327 Added CPE Configuration OR *cpe:2.3:o:linuxfoundation:edge_virtualization_engine:*:*:*:*:*:*:*:* versions up to (excluding) 9.5.0
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2023-43635 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2023-43635
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.04 }} 0.00%
score
0.07202
percentile