If someone nefarious has your full legal name and your phone number, can they wreak any havoc in our life with that info?

I mean, that’s what phone books were.

True but nefarious people didn't have the additional tool of the internet back then.
- Phone books exist online, too.

Nah, nobody can wreck my life better than me.

when someone steals your identity and your credit rating starts going up

Not a whole lot can be done with a first and last name and a phone number. If someone is motivated they don’t need any of this to do harm.

As an example at my job people know my first and last name and I give it to people voluntarily without knowing anything about the other person. While I don’t give out my personal phone number, I know lots of people that do. Sometimes on their business card or even email.

You may be over thinking this and just use it as a lesson to be a bit more guarded and aware of social pressure in the future.

Thank you. After a good night of sleep I agree with your last paragraph.

Have you heard of swatting? Spoof a call from your number to 911 and make up something really bad sounding.

Yes, anything related to spoofing, that's what I was afraid of. But don't they need to know more information to spoof, such as your address and birth date etc?
- No, the phone system is horribly insecure.
- You're either fishing for ideas or you pissed someone off and are scared for they might pull on you.
Doesn't really work outside the US.
- It does I'm in the UK and have been swatted, completely wrecked my life for a few months I was interrogated/interviewed dozens of times in dozens of stations and my dad even got arrested and cautioned during it.
  Worst thing about it as soon as they realise they have messed up they double down on trying to get you on anything.

Probably not without using that information to attain additional details. Things like address, family member's names, job, can all be obtained without leaving their computer for almost no cost (or free, but with less accurate results sometimes).

After that, what they could do is really up to how much effort they put in, contrasted with how much effort you put in to preventing. A swat team could show up at your door with little effort on their part. Or if they wanted to go through the effort of social engineering/dumpster diving/remote hacking their way into enough info to steal your identity.

2FA with strong passwords at a bare minimum. And not "strong" according to the website's account creation page, actually strong (which is itself a moving target to define, and is always in debate).

Any loved ones who may have potential access to sensitive information should also be prepared similarly to avoid some of the more catch-all scams such as phishing.

Spoofing a number means they can call somebody and appears as calling from your number. In order to receive SMS or call made to your number, they would have to hijack your SIM, typically convincing your telecom provider to transfer your phone info over to theirs.

In the US, someone knowing your full name and phone number is commonplace. There is no wide-spead havoc because of this. Someone who wants to harm you would really have to be motivated to get more information from the info you gave them. This is obviously possible because of wide-spread data leaks, but does your emissary have the perseverance and the knowledge to do this?

There have been cases with Verizon where by simply stating your name and phone number they'll just ship anybody the victims sim card. Happened to h3h3. I think they've stopped that now but it's scary knowing your livelihood is at the whim of a min wage call center operator.
In terms of data leaks I've been really lucky, in part since I've been pretty proactive. Extremely careful to rarely give any info to any service, especially social security. Using haveibeenpwned.com will tell you if your info is involved in any data breaches.
- Have I been pawned is really nice, but only includes confirmed data leaks. If you use other services like Google or Malwarebyte, they will tell you more leaks. I was involved with the MoveIt data leak from a financial institution recently, which basically leaked all the information that possibly can be partly/wholely used for identity theft. This didn't show up in HIBP. Fidelity Financial Life Insurance just leaked enough info via Infosys for another 30,000 customers with enough data for identity thefts recently.
  In the US, it seems if somebody is able financially to aggregate all these sensitive data leaks, they probably can cause havocs to many people. These info often come from financial institutions, which you can't totally withhold or lie about your personal information.

That depends very much on which country and culture.

Not where I live as anyone can more or less look that up online for anyone. That's why I find it so fun when I hear those YouTube sponsors about how your full name and your birthday might be online, so pay this company to check for it and try to remove it.

It's not that hard to get both for most people. The phone book whitepages used to list those. There are various services that aggregate them now.

Given that it's not all havoc out there, probably not trivially.

But...by the same token, there's nothing intrinsically about knowing your physical address that would let someone do that. But...they could go firebomb your house or something.

Okay but I just said full name and phone number. Not address. What can they do with JUST a full name and phone number?
- Usually they can look up your address if your name is in any way unique or uncommon, especially if they have your phone number as well. Some sites may show associated email addresses, then there’s things like LinkedIn (if you use it) or other social media sites that link to a name.

Hello my name is Christopher l brown My phone number is 6154183400 We can test and see if anyone can do anything with that info. Please dont use this to come kill or rape me. But you can send me money via my number on like cash or chime.

okay now you're freaking me out because the person who raised concern in me yesterday and why I am posting about this, his name was Christopher.
by the way I'm pretty sure you're not supposed to put phone numbers or identifying information on Lemmy. isn't that against the rules or something
- Well christopher is a very popular name. Theres to many in my opinion.
- You're not allowed to dox other users. You're perfectly free to dox yourself

Relatively speaking, there's no reason to suggest not, especially if there is flexibility of utility, perhaps to the delight of some who slanderously wish to entertain that idea toward me this month.

Your comment is so cryptic I'm just going to leave all of your links blue.
- Sorry, non-native-speaker here. You asked if anyone can do something with certain details. I was trying to say you can never rule out the possibility based on resources. I have a lot of experience being on the receiving end of this, the links being there as a recently relevant relic of that notion.

Just dm me your full name and number we can try it out