CVE-2021-32635
Published: 28 May 2021
Summary
CVE-2021-32635 is a medium-severity Improper Input Validation (CWE-20) vulnerability in Sylabs Singularity. Its CVSS base score is 6.3 (Medium).
Operationally, ranked in the top 29.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-1270
Vulnerability details
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…
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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.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Authorizing wireless access restricts the wireless communication channel to only intended endpoints.
Approving specific exchanges and documenting interface characteristics restricts communication channels to only intended endpoints and systems.
Limits physical connectivity to transmission channels, supporting restriction of communication paths to only intended endpoints.
Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.
Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.
Requiring providers to meet communication-channel restrictions and monitoring adherence reduces improper restriction of channels to intended endpoints.
Mandates restriction of the channel for authentication to only the intended trusted endpoints, blocking unauthorized communication paths.
Explicit control of VoIP traffic forces organizations to restrict communication channels to only intended endpoints and protocols.