CVE-2023-6245

Summary

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 and 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 maximum instruction limit per execution round. Repeated exposure to the payload will result in degraded performance of the canister. Note: Canisters written in Motoko are unaffected.

Affected Software

VendorProductVersion RangeStatus
Internet ComputerCandid0.9.0 < 0.9.10affected

Weaknesses

  • CWE-835: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')
  • CWE-1288: CWE-1288 Improper Validation of Consistency within Input
  • CWE-168: CWE-168 Improper Handling of Inconsistent Special Elements
  • CWE-20: CWE-20 Improper Input Validation

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: yes
    • Technical Impact: partial

References