CVE-2021-32635 Action Commands (run/shell/exec) Against Library URIs Ignore Configured Remote Endpoint

2021-05-2820:20:12

CWE-923

CWE-20

GitHub_M

www.cve.org

singularity

library uri

remote endpoint

bypass

security vulnerability

workaround

patched

container platform

CVSS3

6.3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

LOW

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L

AI Score

6.6

Confidence

High

EPSS

0.002

Percentile

54.3%

JSON

Singularity is an open source container platform. In verions 3.7.2 and 3.7.3, Dde to incorrect use of a default URL, singularity action commands (run/shell/exec) specifying a container using a library:// URI will always attempt to retrieve the container from the default remote endpoint (cloud.sylabs.io) rather than the configured remote endpoint. An attacker may be able to push a malicious container to the default remote endpoint with a URI that is identical to the URI used by a victim with a non-default remote endpoint, thus executing the malicious container. Only action commands (run/shell/exec) against library:// URIs are affected. Other commands such as pull / push respect the configured remote endpoint. The vulnerability is patched in Singularity version 3.7.4. Two possible workarounds exist: Users can only interact with the default remote endpoint, or an installation can have an execution control list configured to restrict execution to containers signed with specific secure keys.

CNA Affected

[
  {
    "product": "singularity",
    "vendor": "sylabs",
    "versions": [
      {
        "status": "affected",
        "version": ">= 3.7.2, <= 3.7.3"
      }
    ]
  }
]