CBSE Blockchain Threat Modeling 3

Question 1

In a blockchain threat model, which data flow diagram (DFD) element represents the PostgreSQL database storing off-chain transaction metadata?

Accepted Answer

Data store

Answer

Process

Answer

External entity

Answer

Trust boundary

Question 2

Which blockchain-specific threat involves an attacker deliberately delaying block propagation to increase the chance that their competing block is accepted?

Accepted Answer

Selfish mining

Answer

Eclipse attack

Answer

Long-range attack

Answer

Grinding attack

Question 3

A threat model for a cross-chain bridge identifies that the bridge's multi-sig wallet requires only 2-of-5 signers. What threat does this primarily expose?

Accepted Answer

Threshold compromise allowing unauthorized fund transfers with only 2 colluding signers

Answer

Denial of service via key exhaustion

Answer

Replay attacks across chains

Answer

Reentrancy in the bridge smart contract

Question 4

Which LINDDUN privacy threat category is most relevant when a blockchain's transaction graph allows de-anonymization of user identities?

Accepted Answer

Linkability

Answer

Non-repudiation

Answer

Unawareness

Answer

Detectability

Question 5

In threat modeling a smart contract upgrade proxy pattern, what is the primary security concern introduced by the upgradeability mechanism?

Accepted Answer

An unauthorized party could replace contract logic to drain funds or change behavior

Answer

Increased gas consumption during execution

Answer

The proxy pattern breaks ERC-20 token compatibility

Answer

Upgradeability prevents formal verification of the contract

Question 6

A threat modeler identifies that validators in a PoS network can be bribed to sign conflicting blocks. Which countermeasure is specifically designed to deter this threat?

Accepted Answer

Slashing conditions that penalize validators for equivocation

Answer

Increasing block size limits

Answer

Adding more validator nodes to the network

Answer

Implementing zero-knowledge proofs for transaction validation

Question 7

When applying PASTA threat modeling to a blockchain application, which phase involves simulating realistic attack scenarios using threat intelligence?

Accepted Answer

Phase 6 – Attack Enumeration and Modeling

Answer

Phase 2 – Define Technical Scope

Answer

Phase 5 – Vulnerability and Weakness Analysis

Answer

Phase 7 – Risk and Impact Analysis