Incident Overview
On September 8, 2025, Swiss crypto platform SwissBorg lost approximately $41.5 million worth of Solana (SOL) tokens when hackers compromised partner API provider Kiln, affecting their SOL Earn program. Around 193,000 SOL tokens were stolen, impacting less than 1% of users, with SwissBorg immediately allocating its SOL treasury to cover user losses and maintain normal operations.
The breach originated from a compromised API at Kiln, a third-party staking infrastructure provider used by SwissBorg's SOL Earn program. The attackers exploited vulnerabilities in Kiln's systems to gain unauthorized access and move approximately 193,000 SOL tokens without triggering internal security alarms at SwissBorg. Since Kiln operates as a backend service provider, the malicious activity went undetected initially as it appeared to be legitimate staking operations.
SwissBorg's core systems remained secure throughout the incident, with the vulnerability existing solely within the third-party integration. The platform responded rapidly by allocating its own SOL treasury holdings to fully reimburse affected users, emphasizing that the company's strong financial health allows it to absorb the loss without impacting other services. SwissBorg has engaged forensic experts, white-hat hackers, and coordinated with exchanges to freeze suspicious transactions while investigating fund recovery options.
Incident Report
Protocol Information
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.
What Auditors Should Check
If you're auditing a protocol with similar architecture to SwissBorg, these are the critical security checks that could have prevented this incident (September 2025).
- Verify all logic paths related to Third-party API compromise / 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
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