Crypto and Web3 Security: protection for exchanges, DeFi and digital asset custody

Why exchanges, DeFi and Web3 are priority targets

Crypto is the only sector in which the protected asset is money itself, transferable instantly, pseudonymously and with no intermediary able to reverse the operation. Once a transaction is confirmed on the blockchain, there is no reversal, chargeback or freezing of the destination account. That changes the whole economics of the attack: the intruder who steals a key or exploits a contract can move funds beyond any reach in minutes, and the cost of the error falls entirely on the exchange, the protocol or the custodian.

The result is a broad, extremely high-value attack surface. Exchanges concentrate the keys of thousands of users in hot wallets to guarantee liquidity; DeFi protocols lock value in public contracts auditable by any adversary; bridges hold reserves that connect networks; and founders and operators become direct targets of social engineering, because compromising a single person with signing access can be worth the entire vault. For those operating in Brazil, regulatory risk is added: with the Central Bank framework in force, the virtual asset service provider also answers to the regulator for security and anti-money-laundering failures.

What is at stake is not just the balance. It is business continuity (a single drainage incident can be fatal to a project), user trust (the base migrates at the first suspicion of insolvency), regulatory exposure and, increasingly, the liability of founders and directors.

Threats and vectors typical of the crypto sector

At the code level, smart contracts concentrate the most expensive flaws. The OWASP Smart Contract Top 10 organizes the most exploited classes, among them improper access control, price oracle manipulation, logic errors, input validation failures, reentrancy, unverified external calls, flash loan attacks, integer overflow/underflow, insecure randomness and denial of service. Classic reentrancy, in which a contract makes an external call before updating its own state and allows repeated withdrawals, remains present despite mature mitigations like ReentrancyGuard. In DeFi, the combination of flash loan with oracle manipulation is today one of the most destructive vectors, distorting prices to drain entire pools in a single transaction.

At the infrastructure and operations level, the decisive vector is the private key. Key compromise through malware on an operator's device, seed phrase leakage, a failure in a multisig signer or in a poorly designed signing ceremony amounts to total loss of the custodied funds. In exchanges, add the exposed API (API keys with excessive permissions, absence of rate limiting, weak IP allowlisting), the withdrawal flow (automatic approval with no second barrier, authorization flaws between accounts) and account hijacking through SIM swap or weak 2FA. Bridges, by interconnecting networks with distinct trust models, accumulate reserves and validators that become an extremely high-value single point of failure.

At the user and reputation level, phishing and drainers have become the highest-volume vector. Fake sites and dApps induce the victim to sign transactions or grant unlimited token approvals, draining the wallet without exploiting any contract vulnerability. Typosquat domains, malicious ads and brand impersonation on free hosting platforms (netlify.app, vercel.app and the like) broaden the reach, hitting both customers and the project's credibility. Leakage of corporate credentials on the dark web closes the cycle, giving the adversary the starting point for internal access.

Regulatory requirements for the crypto sector in Brazil

Brazil is no longer a regulatory vacuum. Law 14.478/2022 established the legal framework for virtual assets, defined what a virtual asset and a virtual asset service provider are, and created a specific criminal offense of fraud with virtual assets (imprisonment of 4 to 8 years and a fine) for anyone who manages, offers or intermediates operations for the purpose of obtaining unlawful advantage. The law assigned to the Executive Branch the designation of the regulatory body, a role that fell to the Central Bank for virtual assets that are not securities — these remain under the jurisdiction of the CVM.

In November 2025, the Central Bank published Resolutions BCB 519, 520 and 521, effective from February 2, 2026, which form the operational framework of the sector. They govern the authorization, incorporation and operation of Virtual Asset Service Providers (also referred to as Sociedades Prestadoras de Serviços de Ativos Virtuais, SPSAV) and the activity of these companies in the foreign exchange market, extending to them much of the regulatory structure applicable to financial institutions, including requirements for governance, risk management, segregation of duties, capital and information security. In practice, exchanges, custodians and intermediaries operating in the country now depend on Central Bank authorization and answer to the regulator for their security posture.

In parallel, cross-cutting obligations apply. LGPD applies in full to users' personal data (KYC, documents, transaction history), with a duty to report security incidents to the ANPD and to the data subject. Anti-money-laundering and counter-terrorism financing (AML/CFT) rules require robust KYC, monitoring of suspicious transactions, sanctions screening and reporting to COAF. Frameworks such as ISO/IEC 27001 and SOC 2, though not mandatory by law, are increasingly required by banking partners, insurers and institutional investors as proof of maturity. Decripte structures the compliance program so these layers talk to each other, rather than becoming isolated documents.

How Decripte implements crypto and Web3 security

Decripte does not sell a report: it implements the crypto project's security function end to end. At the smart contract layer, we perform code auditing against the OWASP Smart Contract Top 10 and market standards, with line-by-line manual review combined with static and symbolic analysis (using tools like Slither and Mythril), protocol-specific threat modeling, testing of reentrancy, oracle manipulation and flash loan scenarios, and retesting after remediation. For live protocols, we integrate this into a continuous cycle, because every contract upgrade is a new surface.

At the exchange and application layer, we run pentesting of the platform, the API and the app, focused on the critical crypto flows: authentication and session, authorization between accounts, withdrawal flow, API key management, rate limiting and protection against automation. We assess and harden 2FA, recommending phishing-resistant authentication (FIDO2/WebAuthn) instead of SMS. In key management, we design and review the cold/hot wallet architecture, MPC schemes and HSM use, signing ceremonies, multisig signer policy and segregation of duties, eliminating single points of compromise.

At the continuous operations layer, the 24x7 SOC combines on-chain monitoring (anomalous movements, interactions with risky addresses, drainage patterns) with credential and brand monitoring (dark web leaks, phishing domains and drainers impersonating the project) and edge protection (WAF and DDoS mitigation). When the worst happens, Incident Response steps in with a containment SLA, on-chain tracing of funds, coordination with exchanges and providers to try to freeze assets, evidence preservation for authorities and insurers, and a recovery and communication plan. All of this is anchored in the free initial Threat Management diagnostic (Decripte Intelligence Center), which already delivers real value before any contract.

Where to start protecting your crypto project

Start with what gives immediate visibility at zero cost: the free Threat Management diagnostic at decripte.com.br/intelligence-center. With no credit card, the Decripte Intelligence Center monitors leakage of credentials tied to your domain, dark web exposure and domain reputation, including phishing and drainer pages trying to impersonate your project. For a sector where the attack usually begins with a leaked credential or a fake site, that alone reduces real risk on day one.

In parallel, prioritize what is irreversible. If you have smart contracts in production or about to deploy, contract auditing is the first priority, because the code is public and the error is final. If you operate an exchange or custody, start with key management and pentesting of the withdrawal flow, the two points where a flaw turns into total loss. Decripte structures this sequence with you and executes it, organizing the delivery order so protection and deadline move together.

When you want to move on to the full services (smart contract auditing, pentesting, 24x7 SOC, incident response and compliance with the Central Bank framework), engage at decripte.io/start or talk to a specialist at decripte.io/contato. The recommended path is clear: turn on the free monitoring now, audit what is irreversible next, and place the operation under 24x7 surveillance to contain any incident before funds leave your reach.

Termos do setor

Smart contract

A program that runs on the blockchain and executes rules automatically, with no intermediary. Because the code is public and operations are irreversible, flaws in it can drain all the locked value, which makes auditing indispensable before deployment and at each update.

MPC (Multi-Party Computation)

A key management technique in which the private key never exists whole in a single place: it is split among several parties that sign transactions jointly. It eliminates the single point of compromise typical of a key or seed phrase stored in isolation.

HSM (Hardware Security Module)

A physical device dedicated to generating, storing and using cryptographic keys so they never leave the hardware. In exchanges and custody, it protects signing keys against extraction by malware or improper server access.

Drainer

A malicious site or dApp that induces the user to sign a transaction or token approval, emptying the wallet without exploiting any smart contract flaw. It is today one of the highest-volume phishing vectors in Web3, attacking the user and the project's reputation.

VASP (Virtual Asset Service Provider)

A figure created by Law 14.478/2022 and regulated by Resolutions BCB 519, 520 and 521 (effective from February 2, 2026), also referred to as SPSAV. Exchanges, custodians and intermediaries operating in Brazil need Central Bank authorization and must meet governance, AML/CFT and information security requirements.

Bridge attack

Exploitation of a bridge connecting different blockchains. Because bridges accumulate reserves and depend on validators or contracts that become an extremely high-value single point of failure, they are a frequent target of large-scale thefts in DeFi.

Por onde começar

1. Turn on the free Threat Management diagnostic today at decripte.com.br/intelligence-center to map leaked credentials, dark web exposure and phishing domains that mimic your project, with no credit card.
2. Audit every smart contract before deployment and at each upgrade, against the OWASP Smart Contract Top 10, combining manual review with static and symbolic analysis (Slither, Mythril) and retesting after fixes.
3. Redesign key management: move reserves to cold storage, adopt MPC and HSM, define multisig signers with segregation of duties and eliminate any single point of compromise.
4. Pentest the exchange, the API and the app with a focus on the withdrawal flow and authorization between accounts, and replace SMS 2FA with phishing-resistant authentication (FIDO2/WebAuthn).
5. Implement robust AML/CFT (KYC, sanctions screening, monitoring of suspicious transactions and reporting to COAF), aligned with Law 14.478/2022 and Resolutions BCB 519, 520 and 521.
6. Place the operation under a 24x7 SOC with on-chain, credential and edge monitoring (WAF/DDoS) to detect drainage and anomalous movements in real time.
7. Have an Incident Response plan ready, with a containment SLA, on-chain tracing of funds and channels to try to freeze assets with exchanges and providers.
8. Engage the full program at decripte.io/start or talk to a specialist at decripte.io/contato to integrate auditing, pentesting, SOC, IR and compliance with the Brazilian regulatory framework.

Perguntas frequentes