CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:L/AC:L/Au:N/C:N/I:P/A:N
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
AI Score
Confidence
High
EPSS
Percentile
12.6%
Cosign provides container signing, verification, and storage in an OCI registry for the sigstore project. Prior to version 1.5.2, Cosign can be manipulated to claim that an entry for a signature exists in the Rekor transparency log even if it doesn’t. This requires the attacker to have pull and push permissions for the signature in OCI. This can happen with both standard signing with a keypair and “keyless signing” with Fulcio. If an attacker has access to the signature in OCI, they can manipulate cosign into believing the entry was stored in Rekor even though it wasn’t. The vulnerability has been patched in v1.5.2 of Cosign. The signature
in the signedEntryTimestamp
provided by Rekor is now compared to the signature
that is being verified. If these don’t match, then an error is returned. If a valid bundle is copied to a different signature, verification should fail. Cosign output now only informs the user that certificates were verified if a certificate was in fact verified. There is currently no known workaround.
[
{
"product": "cosign",
"vendor": "sigstore",
"versions": [
{
"status": "affected",
"version": "< 1.5.2"
}
]
}
]
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:L/AC:L/Au:N/C:N/I:P/A:N
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
AI Score
Confidence
High
EPSS
Percentile
12.6%