Nikolaus from LocalBitcoins reported:
The livechat accounts used by localbitcoins.com were compromised. Within those chats the impostor provided links to download executables, which probably had key loggers or other malicious software.
It currently appears that the number of users impacted by the chat compromise is under 5 with a reported theft under 20 BTC thus far. Nikolaus also reports,
Right now it seems that in total 3 users were affected, and about 17 BTC were stolen through those attacks in total. We will be in touch with those users regarding refunds.
The number of accounts affected seems fairly low at this time, but time will tell how many accounts could be impacted. The chat service on LocalBitcoins was powered by a third-party provider and it is likely that the chat account was compromised.
The compromised chat accounts highlight the importance of providers securing third-party platforms when related to financial products.