96
votes
How and why is my site being abused?
Interesting problem. I wonder if a solution to this problem may be to force your users' web browsers to solve a cryptographic problem (using javascript running in their web browser) that is 'hard' to ...
- 21.6k
89
votes
Accepted
Is it possible to spoof an IP address to an exact number?
You can change your IP to whatever you want; that's trivial. But that will not work the way you want to.
Let's say the store's ISP is Apple Networks, and their IP range is 1.2.3.0 to 1.2.3.255. You ...
- 52.3k
73
votes
Accepted
Can I change my public IP address to a specific one?
You can send out a packet with whatever IP address you like.
Then, one of the routers along the way might decide the packet makes no sense (it is a "martian packet") and discard it. Consider ...
- 22.7k
54
votes
Is it a bad idea to bypass login wall for a specified IP address?
You don't have to worry about spoofing the IP from a different connection, because returned TCP packets would not make it to the attacker in that scenario.
So all you have to worry about is how easy ...
- 13.9k
49
votes
How does IP address spoofing on the Internet work? Who can do it?
IP Spoofing is NOT IP Hijacking which is causing confusion for anyone reading this. IP Spoofing at its minimum / bare bones explanation is also called impersonation. Let's have an ASCII look at what ...
- 8,672
34
votes
How and why is my site being abused?
How?
Rented botnet and captcha farms.
Why?
Someone wants your data. It's cheaper to steal it than buy it.
What to do?
Stealing it is cheaper, but not free. It costs "them" (whoever ...
20
votes
Accepted
Nmap through proxy
TL;DR: proxy support is limited right now but there are also theoretical limits of what you could do when using a proxy.
nmap can do only CONNECT and SOCKS4 and these protocols can do only TCP. ...
- 193k
17
votes
How does IP address spoofing on the Internet work? Who can do it?
IP spoofing means creating IP packets with a source address which is not yours and sending those to some destination. To be able to do so, routers on the path have to allow traffic coming from an ...
- 6,888
17
votes
Is it a bad idea to bypass login wall for a specified IP address?
As others pointed out, IP spoofing alone is not a problem here since the threeway handshake for TCP will not complete.
BGP hijacking combined with IP spoofing could result into a somewhat theoretical ...
- 6,888
14
votes
Accepted
Spoof IP address after a TCP handshake
Is it possible to spoof the IP once a TCP handshake was performed successfully?
No.
A TCP session is defined by four items:
Source IP address
Source IP port
Destination IP address
Destination port
...
- 72.5k
14
votes
Accepted
IP Spoofing: How secure is to control access by user’s public IP address?
Short Answer
Assuming a TCP connection, it is nearly impossible to spoof a source IP address without control of the network.
Longer Answer
Assuming you are not using any proxies (which can cause ...
- 176
14
votes
Is it possible to spoof an IP address to an exact number?
You can spoof your IP to whatever you want it to be. Pick a number, any number! However, you can't use it to trick a HTTP server into believing your are someone you are not. The TCP handshake protects ...
- 65.1k
14
votes
How and why is my site being abused?
If you can put up a simple "type the number in this picture" CAPTCHA and have that stick for 24 hours, you know your enemy is an amateur. You know this sort of primitive device involving ...
14
votes
Can I change my public IP address to a specific one?
Probably not, depending upon whether or not your ISP is implementing Ingress Filtering:
a technique used to ensure that incoming packets are actually from the
networks from which they claim to ...
- 72.5k
13
votes
Can I change my public IP address to a specific one?
Even in the absence of ingress filtering as described in the other answers, IP spoofing will hit another hurdle: the TCP 3-way handshake, and possibly higher-level handshakes.
TCP is the basis for ...
- 3,575
12
votes
How and why is my site being abused?
Why?
Data related to phone numbers, names and email addresses are extremely valuable, both in the legal and underground market.
How?
It sounds like someone is using a botnet to mine data from you. ...
- 221
11
votes
Accepted
Is it possible to send HTTP packet via spoofed IP?
Is it possible to send HTTP packet via spoofed IP?
No you can't.
HTTP is a protocol on top of TCP and doing IP spoofing with TCP is nearly impossible due to the internals of the protocol. You would ...
- 193k
10
votes
Is it a bad idea to bypass login wall for a specified IP address?
I'd say IP spoofing is pretty much on the table here. Nothing stops people which have access to the datacenter infrastructure (e.g. employees) to forge IP packets with the password-free address, and ...
- 10.1k
10
votes
Is BCP38 enough to stop DDOS attacks?
There are types of DDOS attacks which don't use source spoofing and where thus BCP38 does not help. For example the current IoT based DDOS attacks against Dyn, OVH, etc did not use source spoofing at ...
- 193k
9
votes
Accepted
Is IP spoofing still a threat in the Internet?
Yes there is some statistical data about that: http://spoofer.cmand.org/summary.php
// Quoting the referenced Pages FAQ:
Actually, our measurements clearly show that spoofing is still
prevalent ...
- 4,303
9
votes
Difference between X-Forwarded-For IP, X-Real-IP, VPNs and TOR
X-Forwarded-For header may be used to forward client's real IP in case of source NAT. But not all application use them.
This header is often inserted by load-balancers or reverse-proxies, depending ...
- 679
9
votes
Nmap through proxy
For now, use an external tool like proxychains.
The nmap documentation for --proxies states, that the feature is not fully implemented yet:
Warning: this feature is still under development and has ...
- 44.4k
9
votes
Is it possible to send HTTP packet via spoofed IP?
It is not possible
A spoofed http packet would have to travel over a TCP connection.
TCP has a 3-way handshake that would prevent communication from a spoofed IP address from ever reaching the ...
- 6,844
9
votes
Is it possible to spoof an IP address to an exact number?
Practically yes, you can spoof it but it won't help in too many situations.
The IP protocol specifies that each IP packet must have a header which contains the IP address of the source of the packet. ...
- 8,859
7
votes
Is it a bad idea to bypass login wall for a specified IP address?
As the other answers already has shown, it is possible to circumvent this security system. But it requires some effort. The next question is, what you are going to protect and what the easier access ...
- 2,998
6
votes
Is it possible to send HTTP packet via spoofed IP?
Spoiler: you can't.
Smart pants: If you can fit the request in a single TCP packet, you can. Or if you control the routing to the spoofed IP. Or the machine with the IP that is spoofed.
But: you ...
- 14.4k
5
votes
Accepted
Is there a difference in security between an IP address white list and a domain white list with TLS?
tl;dr: different things, both useful for different scenarios, IP whitelisting is not a bad sign
You are indeed comparing apples and oranges.
IP-based filtering happens at the network layer of the ...
- 14.4k
5
votes
Could an attacker spoof a whitelisted IP to access the network?
Nothing prevents an attacker from getting at least one IP packet through to a destination IP address behind a firewall if the hacker spoof's a whitelisted IP address for the packet's source IP address....
- 51
4
votes
Difference between X-Forwarded-For IP, X-Real-IP, VPNs and TOR
The additional headers (usually identifiable by a deprecated convention of using X- as a prefix) are just a convention. And are editable by anyone with access to the plaintext connection between the ...
- 18.5k
Only top scored, non community-wiki answers of a minimum length are eligible