How much was lost in the Telcoin hack?

The Telcoin hack resulted in $1.3M in losses on December 23, 2023.

What attack technique was used in the Telcoin exploit?

The Telcoin exploit utilized Other. Understanding this attack vector is critical for smart contract auditors and developers building secure DeFi protocols.

How can developers prevent similar smart contract attacks?

Preventing smart contract hacks requires a combination of secure coding practices, thorough security audits, and understanding common attack vectors like reentrancy, oracle manipulation, and access control flaws. Smart Contract Hacking (SCH) provides hands-on training to help developers and auditors identify and prevent vulnerabilities before deployment.

Telcoin Hack

TOTAL LOST $1.3M

Medium Dec 23, 2023 Other

Affected Chain 2023 Incident surface

Recovered $1.3M 100.0% returned

All-Time Rank #784 By amount stolen

Auditors 1 Prior security audit

Incident Overview

Quick Summary

Telcoin App, a Polygon-based mobile wallet, was exploited due to a smart contract vulnerability, resulting in the loss of 1,272,782 USD worth of MATIC and ETH.

Details of the Exploit

Telcoin App is a mobile wallet operating on the Polygon chain. On December 23, 2023, the app's proxy smart contract was exploited by an attacker who took advantage of an uninitialized smart contract. This allowed the attacker to gain a large number of TEL tokens.

The stolen funds were then swapped for MATIC and a portion was also swapped for ETH, which was bridged to the Ethereum Mainnet. The total loss from this exploit amounts to approximately 1,272,782 USD worth of MATIC and ETH.

Block Data Reference

Attacker Address:

https://polygonscan.com/address/0xdb4b84f0…f3a5b7

Funds Holder as of Jan 03, 2024:

https://polygonscan.com/address/0x35d2775e…85ff98

Malicious Transactions:

https://polygonscan.com/tx/0x35f50851…1d902d

https://polygonscan.com/tx/0x0b2c7e34…b1c0c3

Malicious Contract Address:

https://polygonscan.com/address/0x10E5C8d3…d8BdE0

Incident Report

Protocol / Project Telcoin

Date of Incident December 23, 2023

Attack Technique Other

Classification Other

Primary Source View Post-Mortem

Protocol Information

Protocol Type Payments

Affected Token TEL

Official Website www.telco.in/

Protocol Twitter/X @telcoin

Team Anonymous

Source Code Verified On-Chain

Market Context at Time of Hack

Token Categories

PoS Medium of Exchange DeFi Identity Payments Wallet Mobile Payment Polygon Ecosystem

Protocol Links

GitHub Discord Reddit Telegram

What the Attacker Needed to Succeed

Understanding the prerequisites for this type of attack helps auditors identify protocols that are most at risk and helps developers build better defenses.

Technical Knowledge Deep understanding of other and Solidity and EVM internals

Capital Required Seed capital to cover gas and initial position setup

On-Chain Access Ability to interact with smart contracts and deploy a custom exploit contract

Protocol Analysis Identification of the exploitable vulnerability in Telcoin's contract logic - root cause: other

Execution Speed Precise transaction ordering and timing to exploit the vulnerability within a single atomic block

Obfuscation Plan A strategy to launder and move stolen funds - typically through mixers, cross-chain bridges, or decentralized DEX swaps to resist tracing

What Auditors Should Check

Could this have been caught in audit? Likely — with a thorough Other audit checklist and test coverage

Audited by Audit Report 1 — still lost $1.3M. Prior audits don't guarantee safety, especially after post-audit code changes.

If you're auditing a protocol with similar architecture to Telcoin, these are the critical security checks that could have prevented this incident (December 2023).

Verify all logic paths related to Other are guarded by proper access controls and input validation
Review privileged functions (owner, admin, governance) for potential abuse vectors - centralization risks should be documented and bounded with timelocks or multi-sigs

Master these auditing techniques with hands-on labs and real exploit scenarios in the Smart Contract Hacking course.

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Funds Recovery

100.0%

Recovered

$1.3M

Net Loss

Security Audit History

Audit Report 1 Report

Post-Incident Timeline

2024-01-12

Telcoin restored stolen user funds fully as the company's CEO told.

Sources & References

01
Source 1 https://twitter.com/telcoin/status/1739394228361310678
02
Web Archive https://archive.is/rUJVq

Threat Assessment

Severity Level

MEDIUM

Attack Vector Other
Root Cause Other
Year 2023

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