226
votes
Accepted
What is the purpose of "gibberish" comments posted to my blog?
They're probing your site. First, whether the comment will be published. Second, note how they use several popular syntaxes for links - it's an attempt to check which of them will result in an actual ...
- 1,921
185
votes
Received a set of SMS/MMS containing 2 photos, a voice message, and a text "I need help" with Google Maps link from a known contact. Is it spam?
This does not seem to be a virus. It is a panic function in some android phones, that allows to send these messages in case you are kidnapped or otherwise in danger by pressing the power button 3 ...
- 7,708
171
votes
Unsubscribe safely
I think the one thing the others (as of this post) hasn't mentioned: Source of the spam
I would say you should differentiate between "Good" spam (Something you signed up for - knowingly, accidentally,...
- 1,441
123
votes
Accepted
What is the purpose of these weird non-spam emails?
This is spam -- but possibly the spammer was not very good at spamming.
The '=EA' bits are Quoted-Printable, an encoding for bytes into ASCII characters. '=EA=85=9F' thus stands for bytes of values ...
- 168k
109
votes
Accepted
Received a set of SMS/MMS containing 2 photos, a voice message, and a text "I need help" with Google Maps link from a known contact. Is it spam?
This is an exact description of the panic feature built into phones as Peter Harmann already said.
Anecdotally I can tell you on my previous Samsung smartphone, I could trigger this exact feature by ...
- 1,736
97
votes
Accepted
Why would a spammer try to get a (normal) image of mine?
There was a psychology experiment where two groups of homeowners went door-to-door and asked, ironically, for people to consent to display a large and ugly sign in their yard that said some form of, "...
- 1,210
84
votes
Accepted
How did I get this email without a "To" field?
Why?
Two explanations:
BCC
Spam
I've often gotten spam where they seem to want to hide to whom it was addressed for some reason. Since I have a catch-all on my domain, it will arrive for me no ...
- 31.8k
63
votes
Accepted
Unsubscribe safely
You should not click on any links. By clicking on the "unsubscribe" link you probably get marked as "Active Reader" which is willing to interact. You also get on the page of the sender, which might ...
- 1,015
62
votes
What is the purpose of "gibberish" comments posted to my blog?
Many spam filters use Bayesian analysis to determine what is spam and what isn't. These work by comparing inbound content with "known good" and/or "known bad" examples and looking for similarities. By ...
- 82k
59
votes
Why would a spammer try to get a (normal) image of mine?
What I miss in the other answers is that an image may contain extremely
useful information about you. A jpg contains blocks like
the EXIF metadata (here in IrfanView):
and even more interesting, the ...
- 739
58
votes
Accepted
How to explain to a customer that spamfilters don't catch everything
Your answer is pretty OK, but you could explain the ongoing "game" between spammers and spamfilters a bit more. This makes it understandable why some spam always will find its way to the customer.
...
- 7,349
47
votes
Accepted
Is this "Domain Registration Service" email a scam?
Yes, this email is a scam. Ignore it!
I work at a major web hosting firm, and our customers receive these emails on a frequent basis. There are a number of characteristics that are visible from this ...
- 486
45
votes
Browser is accepting italic/bold Unicode as part of SPAM email's URL
Previous answers both tell part of the story here, but there's a few different aspects to understand.
Firstly, why do these code points exist? Unicode has the ambition to replace all previous ways of ...
- 3,772
37
votes
Accepted
Getting spam calls from numbers similar to my own
The telephone system has been designed so that a caller can replace their phone number with a fake, and some unscrupulous companies use this to change their number to appear to be local to the person ...
- 17.3k
37
votes
I receive spam despite a captcha, has my wordpress blog been hacked?
Posting spam doesn't require hacking in any ways.
Regarding the captcha, there is two possibilities:
Either the captcha is automatable (I don't know for your website, but I still encounter a lot of ...
- 19k
37
votes
Accepted
How can I get more spam for my honeypot?
Spammers will "scrape" the internet for email addresses and use programs to collect millions of addresses. Or just download them.
If you want your email address to be picked up by spammers, ...
- 123k
35
votes
How did I get this email without a "To" field?
Headers like To, Cc and Bcc are essentially all cosmetic; they don't control the actual receipient of an email according to the SMTP protocol. It's possible to put whatever you like into these fields ...
- 1,445
31
votes
Why would a spammer try to get a (normal) image of mine?
There are so many potential things that could be happening here.
The attacker may try phishing by having you click a malicious link which containing malware such as keyloggers or similar. The attacker ...
- 1,552
30
votes
What is the purpose of "gibberish" comments posted to my blog?
They are trying to confuse any automatic spam filters you might be using.
Random strings are unlikely to trigger any blacklist-based filter, and when you are using a self-learning filter, these ...
- 48.8k
29
votes
Accepted
What does this malicious PHP script do?
The last line performs an eval() of function v78ZFAX() given the two parameters like so:
eval(v78ZFAX($vFHLJ89, $vIIJ30Y));
That first parameter is the part that takes up the bulk of the code. It ...
- 2,658
28
votes
How did this email list a fake recipient?
When mail is sent via SMTP, there are two separate places this sort of information goes, the Envelope (things that are set with SMTP commands) and the Header (the first block of text under the SMTP ...
- 71.7k
27
votes
Why would a spammer try to get a (normal) image of mine?
He may not be trying to get an image, but your confidence. That is why he/she sent his/her (most likely false) picture. Its social engineering at its best.
In the future he/she may ask you to click ...
- 726
26
votes
Accepted
Browser is accepting italic/bold Unicode as part of SPAM email's URL
What you have here are mathematical symbols, see output from unicode text analyzer:
Browser
Codepoint
Name
# Fonts
Script
𝙪
U+1D66A
MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL U
12
Common
𝙯
U+1D66F
...
- 181k
23
votes
How to explain to a customer that spamfilters don't catch everything
The main function of a SPAM filter is to block anything that looks like a SPAM. The objective of an anti-virus software is to detect and remove anything that possess the signature of a virus (worms ...
- 5,210
23
votes
Accepted
Would 'spam' mail really avoid eavesdropping?
It would help if you elaborated on if you are defending from a targeted attack or just being cautious, and what vector the potential adversary would be using to eavesdrop.
That being said, the method ...
- 2,177
22
votes
Accepted
How does Bayesian poisoning work?
There's a good paper published named Bachelor thesis:The Effects of Different Bayesian Poison Methods on the Quality of the Bayesian Spam Filter ‘SpamBayes’ by Martijn Sprengers.
I'll try to make TL;...
- 54.1k
22
votes
What is the purpose of these weird non-spam emails?
This email is most definitely spam (unless you know the sender and/or solicited this mail). Those odd strings are obfuscation techniques, which are a telltale sign of spam. See Tom Leek's answer for ...
- 9,256
21
votes
Accepted
Email unsubscribe handling security
This is a good example for a case where usability and security do not go hand in hand.
A user wants usability: They want to be able to click the link and be unsubscribed. They want this to always work ...
- 29k
20
votes
Why would a spammer try to get a (normal) image of mine?
I just want to add sexting to the list.
They gain your confidence, you start exchanging pictures, innocent at first but getting racier ("she" will do the same, of course), at some point maybe even ...
- 546
19
votes
Getting spam calls from numbers similar to my own
As GdD said, it's CallerID spoofing with the hope of tricking you into answering a 'local' call. I've had this happen where they used my own number as the Caller ID number! I answered because I ...
- 33.6k
Only top scored, non community-wiki answers of a minimum length are eligible