Vulnerability Database

Impact

A vulnerable node can be made to consume very large amounts of memory when handling specially crafted p2p messages sent from an attacker node.

In order to carry out the attack, the attacker establishes a peer connections to the victim, and sends a malicious GetBlockHeadersRequest message with a count of 0, using the Parallax protocol.

In descendants := chain.GetHeadersFrom(num+count-1, count-1), the value of count-1 is passed to the function GetHeadersFrom(number, count uint64) as parameter count. Due to integer overflow, UINT64_MAX value is then passed as the count argument to function GetHeadersFrom(number, count uint64). This allows an attacker to bypass maxHeadersServe and request all headers from the latest block back to the genesis block.

Patches

The fix has been included in the Parallax client version 0.1.4 and onwards.

The vulnerability was patched in: https://github.com/microstack-tech/parallax/commit/f759e9090aaf00a43c616d7cbd133c44bb1ed01e

Workarounds

No workarounds have been made public.

Credit

This issue was disclosed responsibly by DongHan Kim via the Ethereum bug bounty program, the cooperation is appreciated.