PT-2023-32574 · Candid+1 · Candid+1
Venkkatesh-Sekar
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Published
2023-12-08
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Updated
2023-12-13
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CVE-2023-6245
CVSS v3.1
7.5
High
| Vector | AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
Candid versions 0.9.0 through 0.9.9
dfx versions 0.14.4 through 0.15.2-beta.0
Description
The Candid library causes a Denial of Service while parsing a specially crafted payload with
empty data type. For example, if the payload is record { * ; empty } and the canister interface expects record { * }, then the Rust candid decoder treats empty as an extra field required by the type. The problem with the type empty is that the Candid Rust library wrongly categorizes empty as a recoverable error when skipping the field, thus causing an infinite decoding loop. Canisters using affected versions of Candid are exposed to denial of service by causing the decoding to run indefinitely until the canister traps due to reaching the maximum instruction limit per execution round. Repeated exposure to the payload will result in degraded performance of the canister.Recommendations
For Candid versions 0.9.0 through 0.9.9, upgrade the Candid version to 0.9.10 or later.
For dfx versions 0.14.4 through 0.15.2-beta.0, upgrade dfx to version 0.15.2 or later.
As a temporary workaround, consider restricting access to the vulnerable Candid library until a patch is available.
Fix
Infinite Loop
Resource Exhaustion
RCE
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Related Identifiers
Affected Products
Candid
Dfx