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

A data store in a DFD represents any persistent storage system, such as a database holding off-chain metadata.

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

Selfish mining withholds discovered blocks to gain a disproportionate share of block rewards by forcing honest miners to waste work on orphaned chains.

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

A low threshold means only 2 signers need to be compromised or collude for an attacker to authorize fraudulent cross-chain transfers.

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

Linkability in LINDDUN describes the ability to correlate transactions or identities across a system, enabling de-anonymization in transparent blockchains.

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

If the upgrade authorization is misconfigured or compromised, an attacker can swap in malicious logic, undermining the immutability assumption of deployed contracts.

(CBSE) Certified Blockchain Security Expert Practice Test

(CBSE) Certified Blockchain Security Expert Practice Test

CBSE Blockchain Threat Modeling 3