The Twitter and YouTube accounts belonging to the US Central Command were compromised on Monday by people who claimed they hacked sensitive US military PCs and leaked confidential material in support of the Islamic State.

The compromised CENTCOM Twitter account contained graphics and text supporting the Islamic State in Iraq and Syria (ISIS), and it warned the US to expect more hacks. It was carried out by a person or group dubbed the CyberCaliphate. Central Command is one of nine unified commands in the US military. With its area of responsibility covering Afghanistan, Iraq, Syria, and Iran, it leads the US campaign against Islamic State extremists. Monday's attacks appeared to be carried out by the same group that earlier this month commandeered the Twitter accounts of CBS affiliate WBOC-TV and the Albuquerque Journal.

At the time this post was being prepared, there was conflicting evidence supporting the claim that anything more than CENTCOM's Twitter and YouTube accounts were compromised. Files linked in a post on Pastebin contained what appeared to be rosters of US military personnel, including contact information for Army commands and retired Army generals. A separate series of documents, contained in a folder titled war-scenarios, showed PowerPoint slides that appeared to be related to war games exercises involving China, North Korea, and regions in Africa, Indonesia, and the Caspian. One slide in a file titled SOCOM_Africa_Scenario.ppt was dated January 12, 2015. It proposed a CIA operation in Congo and Southern Africa dubbed "Operation Cakewalk" to seize yellowcake uranium. CENTCOM officials confirmed the compromise of the social networking accounts but told CNN none of the leaked documents appeared to be classified.

On the other hand, there are lots of reasons to doubt the breach of sensitive US military systems. For one thing, many of the documents appeared to already be publicly available. But mainly the doubts boil down to this. If attackers did what CyberCaliphate claims, there likely would be much more to leak than a few dozen documents whose sensitivity is debatable. It seems more likely the person or people responsible compromised the e-mail account of someone who posts to the social network accounts and is trying to make the feat look more impressive than it really is. It's also possible the attackers have no affiliation or allegiance at all to ISIS and are merely flying a false flag.

Whatever the case, it will take more time to know if the compromise included sensitive military systems or if it was limited to the much more mundane hijacking of only social networking accounts. If US systems were breached, that will be a major embarrassment for the Pentagon that could also have consequences for US national security. But even if Monday's attack affected only the Twitter and YouTube accounts, it's still a coup for ISIS or whatever group actually carried out the attack. Like the Pentagon, ISIS and other grassroots groups opposing the US know the value of propaganda, which is based more on emotion than on verifiable facts. Regardless of who is behind the campaign and precisely how far it reached, US military officials have been put on the defensive and forced to respond. And countless people have already seen tweets and headlines claiming—gasp!—CENTCOM has been hacked by Islamic extremists. Monday's episode underscores the increasingly blurry line between hacking and guerrilla marketing. Borrowing from the quote long attributed to the late US Senator Hiram Warren Johnson, it shows that the first casualty in the battle over computer security is truth.