Incident Overview
On April 1, 2025, UPCX suffered an exploit, leading to the theft of 18.4M UPC (~$70M). The attacker gained access to the ProxyAdmin contract, upgraded it, and used the withdrawByAdmin function to drain funds from three management accounts.
The attacker compromised the ProxyAdmin contract, which controls contract upgrades. They modified it to introduce a malicious function, withdrawByAdmin, enabling them to transfer 18.4M UPC (~$70M) from three management accounts. The funds remain untouched at address 0xFf7…334, suggesting further laundering or negotiation attempts.
UPCX has suspended deposits/withdrawals but claims user assets are safe while investigations continue.
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 UPCX, these are the critical security checks that could have prevented this incident (April 2025).
- Verify all logic paths related to Upgraded ProxyAdmin + withdrawByAdmin Hack / Access Control are guarded by proper access controls and input validation - see the Access Control Attacks attack class for patterns
- 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.
Free TrialRelated Attack Classes
The technique used in this hack maps to these vulnerability classes in our security curriculum:
Sources & References
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Learn to Prevent the Next UPCX
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