Here's how to protect yourself:
• Ignore instructions to text "STOP" or "NO" to prevent future texts. This is a common ploy by scammers to confirm they have a live, active contact for more cellphone spam, says Landesman. Never dial call-back numbers either.
• Forward the texts to 7726 (SPAM on most keypads). This will alert your cellphone carrier to block future texts from those numbers.
• Anti-malware software is available for many phones. The trade-off may be reduced battery life, so check with your service provider or phone manufacturer for recommendations.
• Install upgrades to your security software. If you suspect an upgrade notification is phony, check with your cellphone or software provider.
• Never store credit card or account log-in information in emails or notes on your cellphone.
• When you get a text promising you a $1,000 gift card, ask yourself: Would anyone really give me that? Know, too, that banks and other legitimate businesses don't send customers unsolicited texts.
Sid Kirchheimer is the author of Scam-Proof Your Life, published by AARP Books/Sterling.