Briefing
On September 23, 2025, the Seedify cross-chain bridge suffered a significant exploit, resulting in the theft of an estimated $1.7 million across multiple blockchain networks. Attackers gained unauthorized access to a developer’s private key, enabling them to mint new SFUND tokens and subsequently drain liquidity pools across BNB Chain, Polygon, Arbitrum, and Base. This incident severely impacted over 64,000 users on the BNB Chain and caused the SFUND token price to plummet by nearly 60%.
Context
Cross-chain bridges, designed to facilitate interoperability between disparate blockchain networks, have historically represented a critical attack surface within the decentralized finance (DeFi) ecosystem. Their complex architectures and the substantial value locked within them make them prime targets for sophisticated threat actors. Prior to this incident, the industry had already witnessed numerous high-profile bridge exploits, underscoring a persistent vulnerability in cross-chain infrastructure.
Analysis
The Seedify exploit was initiated by a suspected North Korean state-affiliated group, “Contagious Interview,” which compromised a developer’s private key. This key provided the attackers with the ability to mint an unauthorized quantity of SFUND tokens through the audited bridge contract. With these newly minted tokens, the attackers systematically drained liquidity from various pools across BNB Chain, Polygon, Arbitrum, and Base, converting the illicitly acquired assets into other cryptocurrencies like BNB and ETH. The success of this attack highlights a critical failure in key management and access control within the protocol’s operational security.
Parameters
- Protocol Targeted → Seedify (SFUND)
- Attack Vector → Cross-chain bridge private key compromise leading to unauthorized token minting
- Total Financial Impact → Approximately $1.7 Million
- Blockchain(s) Affected → BNB Chain, Polygon, Arbitrum, Base
- Affected Users → Over 64,000 on BNB Chain
- Attacker Attribution → Suspected North Korean state-affiliated group “Contagious Interview”
- Token Price Impact → SFUND plunged nearly 60%
Outlook
Immediate mitigation efforts by Seedify included halting trading, blacklisting malicious addresses, and temporarily disabling all bridges. This incident will likely reinforce the necessity for more stringent multi-factor authentication for sensitive keys, enhanced access control mechanisms, and continuous, real-time monitoring of bridge operations. Other protocols utilizing similar cross-chain bridge architectures must reassess their security postures to prevent contagion risk. The involvement of state-sponsored actors also necessitates increased collaboration between security firms, exchanges, and law enforcement for more effective asset recovery and threat intelligence sharing.
