Ripple (XRP) and Verge (XVG) are two cryptocurrencies that attracted many investors in the last months.
Last week attackers hackers the Verge cryptocurrency system by exploiting a vulnerability in its software and forced its developers to hard-fork the currency.
The bug in the cryptocurrency scheme allowed the attacker to mine blocks with bogus timestamps, it seems that attackers were able to generate new blocks at a rate of roughly one per second.
The hacker reportedly making off with $1 million-worth of tokens, the news was later confirmed on Bitcoin Talk forum by the user with the handle “ocminer” of the Suprnova Mining Pools.
“There’s currently a >51% attack going on on XVG which exploits a bug in retargeting in the XVG code. Usually to successfully mine XVG blocks, every “next” block must be of a different algo.. so for example scrypt, then x17, then lyra etc.” wrote ocminer.
“Due to several bugs in the XVG code, you can exploit this feature by mining blocks with a spoofed timestamp. When you submit a mined block (as a malicious miner or pool) you simply set a false timestamp to this block one hour ago and XVG will then “think” the last block mined on that algo was one hour ago. Your next block, the subsequent block will then have the correct time..
And since it’s already an hour ago (at least that is what the network thinks) it will allow this block to be added to the main chain as well.”
OCminer speculated it was a 51 per attack(aka majority attack), this means that hackers in somehow were able to control the majority of the network mining power (hashrate).
The Verge development team finally confirmed on Wednesday the attack that caused the XVG value to drop from $0.07 to $0.05.
We had a small hash attack that lasted about 3 hours earlier this morning, it's been cleared up now. We will be implementing even more redundancy checks for things of this nature in the future! $XVG #vergefam
— vergecurrency (@vergecurrency) April 4, 2018
“The XVG team erroneously forked their entire network to ‘undo’ the exploited blocks, but this resulted in the entire network being unable to sync,” noted cryptocurrency news site The Merkle.
“When the team was made aware of their mistake, they were able to re-sync the network, but still have not completely defeated the issue.”
At the time of writing the Verge currency has recovered all its value.
(Security Affairs – Verge, hacking)