Short answer. Yes. Rule 57, Section 2 expressly allows an order of attachment to be issued either ex parte or upon motion with notice and hearing. A defendant may therefore first learn of the writ when the sheriff arrives — but making a deposit or giving a bond in the amount fixed in the order prevents the levy.
What the law says
An order of attachment may be issued either ex parte or upon motion with notice and hearing by the court in which the action is pending, or by the Court of Appeals or the Supreme Court
Rule 57, Section 2 — Issuance and contents of order. Read the full provision →
Ex parte issuance is expressly allowed
The section's opening words settle the question: An order of attachment may be issued either ex parte or upon motion with notice and hearing by the court in which the action is pending, or by the Court of Appeals or the Supreme Court. Ex parte means the court may act on the applicant's papers alone, without first hearing the party whose property is targeted. The logic is practical — attachment exists to stop assets from disappearing, and advance warning would often defeat the remedy. The safeguards for the other party take a different form, and come afterwards.
What the order must contain
The order is not open-ended. It must require the sheriff of the court to attach so much of the property in the Philippines of the party against whom it is issued, not exempt from execution, as may be sufficient to satisfy the applicant's demand. Three limits sit in that sentence: only property within the Philippines, only property not exempt from execution, and only as much as the demand requires — exclusive of costs. The Rule also allows several writs to issue at the same time to the sheriffs of the courts of different judicial regions, so assets spread around the country can be reached at once.
The built-in escape: deposit or bond
Attachment is avoided if the party makes deposit or gives a bond as hereinafter provided in an amount equal to that fixed in the order. That amount may be the amount sufficient to satisfy the applicant's demand or the value of the property to be attached as stated by the applicant. In plain terms: substitute security for the property, and the property stays free. For a business whose operating assets are at risk, this is usually the fastest response — the security answers for any judgment while the company keeps trading with its assets intact.
If your property has just been attached
Being caught by an ex parte writ is not the end of the matter. Apart from posting the deposit or bond, Rule 57 lets the party move to discharge an attachment that was improperly or irregularly issued or enforced, or whose bond is insufficient — that is Section 13 of the same Rule. Gather the order and writ themselves, the applicant's affidavit, and the attachment bond, because every remedy starts from what those papers claim. Compare the ground invoked against what actually happened; the gap between the two is where the challenge lives.