ViaBTC, creator of Bitcoin Cash, temporarily suspended the withdrawals of its lever by a suffering that a malleability attack of the transactions.
This occurs because Bitcoin's replicated code has a vulnerability that allows the transactions to be modified by a third party, which may be a node that retransmits the transaction or a miner that includes the transaction in a block with which it alters the transaction identifier. The result is that transactions that have been affected by the malleability attack can not be verified at the time of the transaction, but does not imply that a double expense will be incurred.
It is an alteration in the hash of a transaction without private firms becoming involved in the knowledge of the alteration. In principle, user funds remain safe and can be received by the recipient, although normally under these circumstances the confirmation times are greatly extended.
The malleability attack that ViaBTC confirmed through its Twitter account could not represent a risk for the integration of client funds, but could be a warning related to the position assumed by the group to the problems of scalability of the Bitcoin red.
I saw in their twitter this the other day, is this still the case? because it seems that they have allowed withdraws again:
https://twitter.com/ViaBTC/status/893814961721430016It is ironic that they were attacked with malleability attack, which segwit solves, and they fought so hard against segwit.
How did they allow withdraws again? how did they fix it? because if you check the comments on that tweet, everyone is still complaining about it.