A server outage affecting the Los Angeles Times and other Tribune Publishing-linked newspapers has been identified as a foreign-based cyberattack.

The malware attack, which spread a “Ryuk” computer virus through the company’s network last week, caused delays in production and delivery this weekend, the Los Angeles Times reported Saturday. A source told the outlet, however, that it was too early to tell whether the attack — signs of which were first noticed late Thursday — was sponsored by a foreign government or just a rogue group looking to “disable infrastructure” rather than “steal information.”