Questions tagged [network]

Security of network infrastructure and network traffic. For questions about security of network equipment, topology, protocols, traffic, administration, and configuration. Related tags: [packet], [firewall], [network-scanners], [network-access-control].

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21
votes
5answers
5k views

Unidirectional continuous data transfer to an air-gapped computer

What would be a way to transfer files in one direction from internet-facing computerA => air-gapped computerB to protect the files on computerB from unauthorised disclosure, short of using an ...
21
votes
9answers
6k views

Securing a LAN that has multiple exposed external Cat 6 cable runs?

We're evaluating putting in an IP-based CCTV system for a third-party upcoming project (part of a wider networking project). The CCTV system is cabled as follows: Cat 6 running from each external ...
21
votes
5answers
14k views

Do you detect/react to DNS tunnelling?

I've just seen a talk about tunnelling TCP/IP over DNS requests, because port 53 UDP is usually open and unfiltered. What techniques exist to detect and block such tunnels, and have you ever seen that ...
21
votes
1answer
7k views

SFTP, FTPS and SecureFTP differences and security implications

What are the basic differences and security implications of using SFTP, FTPS and SecureFTP.
21
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3answers
7k views

What are the risks of using a CDN to speed up my website? How do I avoid them? [duplicate]

Content Delivery Networks (CDNs) are well known to speed up the performance of a website, but they create the obvious security risks if someone were to change the code that resides on the CDN. What ...
20
votes
6answers
43k views

What is the best practice for placing database servers in secure network topologies

I have a classic DMZ architecture: My webserver is placed in the DMZ. The webserver needs to communicate with a database server. This database server is the most critical component of my network as ...
20
votes
4answers
10k views

Can an attacker sniff Mac addresses on a wifi?

If an attacker turns on wifi but doesn't have the security key to connect to an access point in range, can he still sniff packets that travel between the access point and clients connected to the ...
20
votes
4answers
32k views

DHCP vs. Static IP Addressing

How do DHCP and Static IP addressing compare, from a security standpoint? What are the risks/benefits associated with each? I know the preferred solution between the two will vary with network size ...
20
votes
3answers
7k views

Are open wireless networks unencrypted?

When you connect to an open wireless network (that is, a wireless network without any symmetric password set) is there any sort of secure key exchange going on, or is data sent back and forth ...
20
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4answers
18k views

Can home routers get infected?

I am behind a router(linksys that runs dd wrt on it) and I was infected with sality. I'm curious, can my router get infected too? If yes, how can I remove the infection? I used the search bar but ...
20
votes
1answer
55k views

EAP-TLS vs EAP-TTLS vs EAP-PEAP

I'm having troubles understanding the differences between the 3. As far as I understand, with EAP-TLS, the client (peer) and the server (authenticator) both need a certificate. The authentication is ...
20
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1answer
14k views

How can I detect real location of the user through their IP address?

There were many ways to detect the user's IP, for instance we could get it through a single click link or through any other medium of communication where we could get the user's IP. But the tedious ...
19
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5answers
3k views

419 Nigerian scam problem

I fell in a scamming trap. It took me a while to figure it out. Blinded like an idiot. But it is what it is. I can only do as much as I can now. Tell me if there is anything else I should do. After ...
19
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6answers
15k views

Are some uncommon TCP ports scanned less than others?

Ignoring the top 5-10% of port numbers for common services that are the commonly targeted by port scanners (i.e. ports 22-ssh, 23-telnet, 80-http, 139-smb/cifs, 443-https, 3389-rdp, etc.), are the ...
19
votes
3answers
5k views

How Can I Process Untrusted Data Sources Securely? [closed]

Here is the conundrum: At my current company, we process physical discs from numerous third party sources and extract the data from them to ingest to our own system. While we can generally trust the ...
19
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4answers
5k views

Is strategic cyber-warfare feasible today?

Cyber attacks that target a nation's infrastructure are a documented fact and as such a danger that political and military leadership across the world needs to worry about and act proactively. These ...
19
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4answers
4k views

Detect non HTTP packets using port 80

We are currently doing port whitelisting on our firewalls which is working well but this of course does not prevent the implementation of side channels or the misuse of these ports for other purposes. ...
19
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4answers
65k views

How to tell if you're being ARP poisoned?

I am having some issues at work and there is a new network admin in place. I think I am being monitored so decided to run ArpSpy X in two scenarios: Over WiFi bridge plugged into Cisco router to took ...
19
votes
4answers
4k views

Threat assesment for a captive portal

I am interested in setting up a captive portal on a wireless network. From what I understand I would do this by initially having all guests in a temporary vlan, moving them to the real vlan when ...
19
votes
4answers
66k views

Pros/cons of using a private DNS vs. a public DNS

I was wondering why a company should use a private DNS. In comparison with a public DNS, which advantages does a private one have, and which issues can a public DNS create for a company? I'm new at ...
18
votes
6answers
4k views

Defamatory post - obtaining evidence tracing perpetrator right to his laptop

A month ago, someone posted an ad with my personal details, including my home address, my phone number and my photo on an ad with very a very defamatory write up. What followed was a week of calls ...
18
votes
3answers
62k views

How can I detect if someone is sniffing network packets on the LAN?

I would like to know if there is a product or software that can detect if there is a sniffer currently on the network? In other words is it possible at all to detect if there is a network card on ...
18
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6answers
18k views

What reputable site should I download Putty from?

I recently did a Bing search for Putty and can only guess at which distribution is "trusted", contains no malware, or sleuthing code. If you needed to download Putty for a high security Windows ...
18
votes
3answers
31k views

How do I ensure data encryption on Samba transmission on *NIX systems?

I have a heterogeneous system (both MS and *nix) that communicates with CIFS/SMB. How can I ensure proper data encryption at the application layer?
18
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1answer
15k views

Is it even possible to hack a television channel?

In spite of all the hacking news in the recent few years I never heard of someone who managed to hack a TV channel. What makes them so secure?
18
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3answers
6k views

Recommendations for honeypot software

A couple of us wanted to setup a honeypot/honeynet with the goal of learning; not planned to be in a production environment. What's a good recommendation for a high interaction or low interaction ...
17
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4answers
52k views

How does Team Viewer establish a Remote Desktop Connection?

I am wondering how is it possible for Team Viewer to establish the remote desktop connection over the internet even if the user has not enabled the 3389 port ? I am searching over the internet but ...
17
votes
8answers
26k views

Why is ARP poisoning killing all network activity?

Using ettercap and ARP poisoning, I was able to eavesdrop on other connections, but suddenly I was unable to make any connection to the Internet. To restore Internet connectivity, I had to restart my ...
17
votes
3answers
15k views

Running windows in virtual machine, should I bother with security?

I'm running Windows in a virtual machine on my mac (via Parallels). Should I bother installing antivirus, firewall and using other conventional wisdom practices (like don't open unknown .exe etc)? I ...
17
votes
1answer
4k views

Cybersecurity “Airport model”

For the last few months, I have heard about a next generation model of Cybersecurity called the "Airport model." Does anyone have more information about it?
17
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4answers
14k views

Best way to report a foreigner attacker's ip to authorities?

I have been under attack last week and I was able to trace down the attacker and get his IP address. The attacker was located in Germany but I live out of Europe? From your experience what is the ...
17
votes
5answers
5k views

Why don't ISPs filter on source address to prevent spoofing?

I'm under the impression that if all the ISPs were required to filter on the source IP address of all outbound packets, that spoofing would be reduced considerably. Are any ISPs implementing this ...
17
votes
2answers
3k views

Potential risks of publicly uploading a Wireshark trace with TLS-related information?

Say I were to upload a Wireshark trace to a website that was publicly available. Say, with it, the SSL key log, certificate information, etc were available. If someone had the link to the trace, what ...
17
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4answers
2k views

Network Forensics - what is in your toolbox

In similar vein to this question on computer forensics, what tools would you have in your toolbox for infrastructure and network forensics. Typical example cases would be if you were called in either ...
17
votes
4answers
56k views

Nmap says host down when host is up

I am using Nmap 7.12 on Mac OS X. The host that is being scanned is a Linux RHEL server in VirtualBox. I can ping the server and receive ICMP replies and vice versa. I am scanning an IP inside the ...
16
votes
2answers
2k views

Hosting an “IP Rental” address. Is this common, safe?

I have a supposed opportunity to get in with an individual with advertising and a side business of his, renting IP addresses. He has asked me to set a dedicated DSL account at my house. Is there any ...
16
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5answers
4k views

Are consumer-grade routers any more or less vulnerable? [closed]

I apologize if this is an obvious question, I'm not very familiar with hardware. I am planning on hosting a few personal websites from my home, but I'm concerned about my security. I'm using a fairly ...
16
votes
4answers
6k views

Security risk of connecting to two networks simultaneously

My employer issues a list of security recommendations when using a work laptop outside of the work network. The security recommendations are related to such risks as data theft, viruses, or other ...
16
votes
4answers
41k views

Tips for a secure iptables config to defend from attacks. (client side!)

Own examples: ############### # KERNEL PARAMETER CONFIGURATION # PREVENT YOU SYSTEM FROM ANSWERING ICMP ECHO REQUESTS echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all # DROP ICMP ECHO-REQUEST ...
16
votes
3answers
20k views

What is the difference between SSH and IPsec?

There seems to be similar encryption going into both. They both use asymmetric (RSA, elliptic curves, etc) for the initial key exchange, then go to some symmetric (AES, Blowfish, etc) protocol. I'm ...
16
votes
4answers
54k views

Detecting(and locating) rogue DHCP server on a local area network

How would we detect and locate a rogue DHCP server on our local area network?
16
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2answers
25k views

Securing remotely accessible IP cameras that do not support HTTPS

I have some IP cameras set up on my home network, which is WPA2 protected. These cameras are setup to be accessible from the Internet thru my router's DDNS address, and port number. So for example, ...
16
votes
2answers
2k views

Network policies under AppArmor/SELinux

I am attempting to sandbox some untrusted processes using Linux's MAC frameworks -- either SELinux or AppArmor. I see that both SELinux and AppArmor allow the selected granting of socket level access ...
16
votes
2answers
7k views

How bad is the leaking of Internal IP addresses through external DNS

If an external DNS server is leaking internal IP addresses are there any significant security threats associated with this information leakage? Apart from most the obvious - gaining an understanding ...
16
votes
3answers
22k views

Pros and cons of disabling TCP timestamps

So, lynis informs me that I should unset net.ipv4.tcp_timestamps. I know that's a bad thing because an attacker could figure out which updates that require restarting the machine I haven't applied, or ...
16
votes
1answer
1k views

Do any DNS registrars support multi factor authentication?

I am looking for a DNS registrar that supports strong multi-factor authentication. Does any DNS registrar support multi-factor? Is this a legitimate need?
16
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3answers
1k views

What techniques and tools do you use to relate security events?

You have central logging going, detailed app logging/alerting (e.g. modsec), network based security alerting (e.g. snort), and whatever else feeding your observation deck. Do you have any cool ...
15
votes
3answers
5k views

Bruteforce attack on my FTP server

I recently setup VSFTPD on my personal server for sharing files over FTP. In the vsftpd.log file, i see hundreds of failed attempts to login with usernames like "adminitrator" , "adminitrator1", "...
15
votes
5answers
30k views

Can I block based on MAC address?

If I block an IP, the attacker can work around the block by taking a new IP or use a proxy. Is it possible to make a ban based on MAC address? I want to block at the webserver level so that unwanted ...
15
votes
3answers
1k views

Would publishing a network diagram make the network less secure?

I have found some social networking sites that focus on sharing architecture (network maps and diagrams) and configuration. Does sharing this type of information decrease the security of my network? ...

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