CVE Vulnerability

CVE-2021-43837

vault-cli is a configurable command-line interface tool (and python library) to interact with Hashicorp Vault. In versions before 3.0.0 vault-cli features the ability for rendering templated values. When a secret starts with the prefix `!template!`, vault-cli interprets the rest of the contents of the secret as a Jinja2 template. Jinja2 is a powerful templating engine and is not designed to safely render arbitrary templates. An attacker controlling a jinja2 template rendered on a machine can trigger arbitrary code, making this a Remote Code Execution (RCE) risk. If the content of the vault can be completely trusted, then this is not a problem. Otherwise, if your threat model includes cases where an attacker can manipulate a secret value read from the vault using vault-cli, then this vulnerability may impact you. In 3.0.0, the code related to interpreting vault templated secrets has been removed entirely. Users are advised to upgrade as soon as possible. For users unable to upgrade a workaround does exist. Using the environment variable `VAULT_CLI_RENDER=false` or the flag `--no-render` (placed between `vault-cli` and the subcommand, e.g. `vault-cli --no-render get-all`) or adding `render: false` to the vault-cli configuration yaml file disables rendering and removes the vulnerability. Using the python library, you can use: `vault_cli.get_client(render=False)` when creating your client to get a client that will not render templated secrets and thus operates securely.

9 /10

CVSS v2.0 :

V3 Legend

Vector :

Exploitability : 8 / Impact : 10

Attack Vector

Attack Complexity

Privileges Required

User Interaction

Confidentiality Impact COMPLETE

Integrity Impact COMPLETE

Availability Impact COMPLETE

Scope

9.1 /10

CVSS v3.0 : CRITICAL

V3 Legend

Vector :

Exploitability : 2.3 / Impact : 6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required HIGH

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

References
Link Resource
https://github.com/peopledoc/vault-cli/commit/3ba3955887fd6b7d4d646c8b260f21cebf5db852 Patch Third Party Advisory
https://podalirius.net/en/publications/grehack-2021-optimizing-ssti-payloads-for-jinja2/ Exploit Third Party Advisory
https://github.com/peopledoc/vault-cli/security/advisories/GHSA-q34h-97wf-8r8j Exploit Mitigation
Configurations

Configuration 1

cpe:2.3:a:vault-cli_project:vault-cli:*:*:*:*:*:python:*:*
Information

Published : 2021-12-16 07:15

Updated : 2022-08-09 01:23

NVD link : CVE-2021-43837

Mitre link : CVE-2021-43837

Products Affected
No products.
CWE
CWE-94