Rather than compromising Google's service directly, it appears as if the hackers breached MYNIC, the Malaysia-based domain name service that runs addresses that end with .com.my. On the upside, this means that there's no risk that personal data could have been compromised, but it's still an inconvenience nevertheless.

Getting reports some users are experiencing http://t.co/uIvl6RbDzu DNS redirection. Please use http://t.co/AdkzwxVR4U in the meantime. - Google Malaysia (@GoogleMsia) April 14, 2015

If the page users were redirected to is to be believed, the hack was the work of Bangladeshi hacker TiGER-M@TE, who has previously hacked Google Bangladesh in 2011. Until the problem has been fixed, users are asked to visit Google via its no-country redirect site at google.com/ncr.