The phrase "attack has appeared" is correct and usable in written English.
It can be used in contexts where you are describing the emergence or occurrence of an attack, such as in a report or narrative.
Example: "In the latest update, it was confirmed that an attack has appeared on the eastern front, prompting immediate military response."
Alternatives: "attack has emerged" or "attack has surfaced".
With their development, a new attack called a path-based DoS (PDoS) attack has appeared.
The 28-year-old man charged with murder in relation to this attack has appeared in Christchurch District Court this morning.
An Australian teenager who was allegedly planning a bomb attack has appeared in children's court charged with terrorism offences.
No official documentation of either supposed attack has appeared, nor has the FCC released any data on it, even a year later and long after the comment period has closed, improvements to the system have been made and the CIO who evaded senators' questions departed.
Relatively few injury victims from the World Trade Center attack have appeared, raising fears that most victims are dead.
The man accused of murdering 50 people in the New Zealand mosque attacks has appeared via video link in the Christchurch high court, in his second formal court appearance since the shootings.
In the prelude to the offensive, drone attacks have appeared to try to home in on Mr. Mehsud and forces loyal to him.
On blogs where attacks have appeared, the researchers point out that many of the accusations, like The Sunday Times's assertion that the scientists implant devices in the brains of the sheep, are simply false.
Allegations of chlorine gas attacks have appeared again in the news on 11 August, this time resulting in the deaths of one woman and two children as well as a formal investigation by the UN.
But while Wales' attacking game has appeared blunt and lacking in variety for some time, what is often overlooked is that their last two Grand Slams were forged on defence.
Salah Abdeslam, a key suspect in the Paris attacks in November, has appeared before French judges on charges of murder and being part of a terrorist organisation.
