blob: 3286889f2f3e146a86474da302b4b36f21b1237f [file] [log] [blame]
- module:
- introduced: 3.0.0+incompatible
fixed: 3.6.0
summary: Execution Control List (ECL) Is Insecure in Singularity
description: |-
### Impact
The Singularity Execution Control List (ECL) allows system administrators to set
up a policy that defines rules about what signature(s) must be (or must not be)
present on a SIF container image for it to be permitted to run.
In Singularity 3.x versions below 3.6.0, the following issues allow the ECL to
be bypassed by a malicious user:
* Image integrity is not validated when an ECL policy is enforced.
* The fingerprint required by the ECL is compared against the signature object
descriptor(s) in the SIF file, rather than to a cryptographically validated
signature. Thus, it is trivial to craft an arbitrary payload which will be
permitted to run, even if the attacker does not have access to the private key
associated with the fingerprint(s) configured in the ECL.
### Patches
These issues are addressed in Singularity 3.6.0.
All users are advised to upgrade to 3.6.0. Note that Singularity 3.6.0 uses a
new signature format that is necessarily incompatible with Singularity < 3.6.0 -
e.g. Singularity 3.5.3 cannot verify containers signed by 3.6.0.
Version 3.6.0 includes a `legacyinsecure` option that can be set to
`legacyinsecure = true` in `ecl.toml` to allow the ECL to perform verification
of the older, and insecure, legacy signatures for compatibility with existing
containers. This does not guarantee that containers have not been modified since
signing, due to other issues in the legacy signature format. The option should
be used only to temporarily ease the transition to containers signed with the
new 3.6.0 signature format.
### Workarounds
This issue affects any installation of Singularity configured to use the
Execution Control List (ECL) functionality. There is no workaround if ECL is
### For more information
General questions about the impact of the advisory / changes made in the 3.6.0
release can be asked in the:
* [Singularity Slack Channel](
* [Singularity Mailing
Any sensitive security concerns should be directed to:
See our Security Policy here:
- CVE-2020-13845
- GHSA-pmfr-63c2-jr5c
- web:
- advisory:
- web:
- web:
- web:
- web:
- 'lint: bad version "3.6.0": invalid version: should be v0 or v1, not v3'
- 'lint: redundant non-advisory reference to GHSA-pmfr-63c2-jr5c'