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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11
votes
6answers
20k views

Automated tools for Cisco IOS config auditing? [closed]

Are there any automated tools for auditing config files exported from Cisco IOS devices? Free/Open Source is always nice, but anything that does the job would be of interest.
11
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3answers
13k views

Security measures for a WiFi access point?

I am planning to purchase a program that comes with an App that allows you to control the program via phone. The developer told me that the connection will be done via an extra WIFI box connecting to ...
11
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4answers
1k views

What is the risk of a packet being sniffed when travelling over the internet without SSL/TLS?

We all know to use SSL/TLS to stop people eavesdropping on our connection, but how likely is it that an attacker will actually sniff your unencrypted password or cookie if you don't? If we exclude ...
11
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3answers
2k views

What free tools or techniques exist to discover anomalies in network flows?

I have been using FlowMatrix. What do others do on the cheap?
11
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4answers
21k views

When does one require netbios?

I've heard others talk of disabling netbios, but over the years I have never understood exactly when this protocol is required. The wikipedia page explains very abstractly what it is, but not which ...
11
votes
4answers
5k views

Is my network being sniffed?

Is there any way to find out if someone who is connected to my network is sniffing packets? There is a way with nmap if his card is in promiscuous mode but what if it is passive?
11
votes
1answer
2k views

How secure is the apt-get install command against man in the middle attacks

I think the title says everything, how secure is it to use apt-get in a network with an attacker who injects his own packets and blocks the original packets (man in the middle).
11
votes
3answers
1k views

Tools needed to setup a paranoid remote backup server

I'm a system admin with little security experience. I want to schedule the copying of our backups to protect our data in case of fire. The best solution would be to copy the data onto a new hard-...
11
votes
3answers
27k views

When do I use IPsec tunnel mode or transport mode?

I basically understand how tunnel mode and transport mode works, but I don't know when I should use one instead of another. Among the two parties who want to communicate, if one computer B doesn't ...
11
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1answer
3k views

Bypassing hidden SSID and MAC filtering “protection”

I was browsing over this question and had some follow up questions from a practical perspective. What tools will show the SSID of an AP with the SSID set to hidden or broadcasting disabled? I have ...
11
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3answers
1k views

How did the spammers get this address?

A few months ago I configured a test mail server on Amazon AWS, all legit. I used a new address to my catchall-domain (something similar to, but not exactly, test-config-aws-neptune-2014-08@my-domain....
11
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2answers
2k views

Online SQL Server database for a Business app. Security considerations

A business application works with a SQL Server database. A SQL Server 2008 is installed on one of the computers of the local network. Technically this app works OK if the server computer with the SQL ...
11
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2answers
7k views

Obtain credentials by spoofing WPA/WPA2 Enterprise network?

I have a large scale wireless network secured using WPA/WPA2 Enterprise authentication. Recently, I was made aware of the possibility that someone may use a dd-wrt router and a computer to spoof the ...
10
votes
4answers
5k views

How to prevent network administrators from accessing USB drive

How can I prevent network administrators from accessing, mapping to etc. a USB drive that's in a PC on their network? I'm mainly concerned about files being edited or deleted.
10
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3answers
3k views

Can an infected phone infect other computers in a network?

Can an infected phone infect other computers in a network? For example do you need to worry about private phones in a company enviroment? Or is that already paranoid?
10
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3answers
2k views

Is it possible that authorities can't block a certain website

I was watching a very recent TV show, the FBI agent told the police that there is no way for anybody to block a live stream of a pedophile torturing a kid nor to trace it. Even when it's being ...
10
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4answers
2k views

Network administrator knowing all user passwords

Whenever it is time to change passwords, each user in our office has to provide our new password to the IT department and they change it & store it. Can you provide something that details why this ...
10
votes
2answers
3k views

Are hacked email addresses a local network or web server problem? [closed]

I work at a small nonprofit and woke up to find that many of our email addresses have been sending spam asking recipients to open an attachment (doc file). We have a local network that all of our ...
10
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5answers
15k views

Is the US military secret network SIPRNet physically or cryptographicaly separated/secured?

I've read the Wikipedia articles on SIPRNet and NIPRNet (which are pretty light on details) and they are supposed to be considered separate. At the network level, are they technologically ...
10
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2answers
3k views

How does HSTS stop MitM attacks?

I know that until a few years ago, someone could set up a fake wireless AP, and use something like SSLStrip to lure the victims into connecting to insecure versions of the major websites, such as ...
10
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8answers
1k views

Battling Malware without spending money

Our environment consists of about 80 users running Windows 7. Previous to me showing up as a full time IT employee, the company had contracted an outsource IT solution. As part of their set up, they ...
10
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5answers
3k views

How can an access point spoof me into connecting?

I was reading through the answers of the question "How can I ensure that I connect to the right wireless Access Point?" and was wondering how it is possible for an access point to imitate another wifi ...
10
votes
6answers
483 views

Should we configure all devices to never request SSL 2.0, and reject it if offered?

In an effort to reduce man in the middle attacks, when will it be (or was it) an industry accepted practice to reject SSL 2.0 connections on the client and server side? Is configuring this on a proxy ...
10
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7answers
3k views

Alternative to VPN

We have a network that is completely closed to the outside world. It needs to be. Problem is we need to remote into a server on this network once in a blue moon for diagnostics. We've discussed ways ...
10
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4answers
11k views

How to break MAC address filtering?

If a MAC filter prevents you from connecting to a network, how can you break it or include your device's MAC in that filter?
10
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2answers
613 views

How were weak passwords brute forced in github?

Github faced a brute force password-guessing attack recently that involved "nearly 40K unique IP addresses". Passwords were also "stored properly" using bcrypt, (salt + hashed). Given that bcrypt ...
10
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3answers
13k views

TCP Sequence Prediction and it's prominence in modern systems/networks

I have a question regarding your experience of TCP Sequence Prediction that I am hoping someone could help with. I am aware of how TCP Sequence Prediction works and how the connection can be hijacked ...
10
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5answers
2k views

How can a company reduce exposure to packet spoofing? What solution should exist, but doesn't?

I'd like to understand what anti-packet-spoofing technology exists (or should exist) to verify an inbound packet. Maybe this is as simple as a Cisco ACL, Firewall Rule, implemented at the network ...
10
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7answers
3k views

How can I restrict access to network data by an unauthorized computer that connects via Ethernet?

I assume I can configure most routers to only assign IP addresses to specific MAC addresses, as is possible with wireless routers. However what if a computer is connected via Ethernet and does not ...
10
votes
2answers
19k views

Recommended Cipher Suites for TLS 1.0, 1.1 and 1.2

There are a lot of cipher suites defined in the in the specifications itself of TLS 1.0, 1.1 and 1.2. And furthermore, there exist RFCs which add even more cipher suites to a specific version (e.g. ...
10
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3answers
11k views

Doesn't an IP conflict occur when ARP spoofing?

I am playing around with Ettercap and ARP spoofing attacks. I have noticed that the computers that are involved in my attack not are displaying any messages telling that an IP conflict has occured. ...
10
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3answers
3k views

Can an attacker “simulate” a private IP address?

I have a SSH server with a rule that does not allow password connections outside the local network. So people already on the local network, either physically or via VPN, are allowed to connect with ...
10
votes
1answer
3k views

Backtrack 5 in a VM - Why bridged networking over NAT?

When running Backtrack 5 from a VM, it is recommended to use the bridged networking option instead of the NAT networking option? How does it affect the usage of Backtrack - port scanning, ...
10
votes
2answers
40k views

Is NAT Loopback on my router a security problem?

Some DSL routers prevent NAT loopback. Security is sometimes cited as the reason. Is NAT loopback really a security issue? And if so, how is this exploited? NAT loopback... where a machine on the LAN ...
10
votes
1answer
5k views

TCP “off-path” Attack (CVE-2016-5696)

Today I read that a flaw in a recent TCP specification leads to the injection of malicious content between the two communicating parties. How does the attack vector work? I have also read a post in ...
10
votes
2answers
3k views

How do the root servers get updated with my name server? Is WhoIS information always in sync with the root?

I've never understood what happens behind the scenes when I go to my registrar and enter in my name server's information. Can someone elaborate on what happens when an update is made, and how it is ...
10
votes
1answer
3k views

ports blocked by firewall and not the server

I was asked this question at an interview and i wasn't sure about the answer. The question was "suppose you were checking the open ports on a particular webserver which was behind a firewall, how ...
10
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2answers
2k views

Malware known to use port knocking to evade detection by network scanners?

Are there any known cases of malware in the wild that utilize port knocking on a backdoor to evade detection by network scanners?
10
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3answers
4k views

Secure PXE network OS installation

How can one make sure that when PXE is being used to boot a remote operating system, that the data being sent is encrypted (or at the very least that integrity is maintained)? Would it be possible to ...
10
votes
3answers
31k 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 ...
9
votes
8answers
36k views

How to block some websites and torrent usage in a small office?

In my office there are approaximately 25 systems are connected through network and all having internet accessibility.but some people are missusing this facilities like downloading films from torrent ...
9
votes
6answers
39k views

Using Python for security [closed]

I love using Python for the scripts I need and for work. But I really want to learn Python for network security since I will start a NS course next year. My question would be how would it be the best ...
9
votes
4answers
6k views

extract from pcap all protocols found

I have some pcap files, and i would like just to get a list of protocols that are present on that pcap file. I would like it in a batch mode, not using wireshark I think tshark is able to do it, but ...
9
votes
4answers
453 views

What are the main security considerations that must be taken into account if you intend on creating a (localised) whistleblower website?

Also: Is it something that can be achieved with limited funds? I ask because I am intrigued by the obstacles that are in place.
9
votes
2answers
17k views

sniffing/recording GSM 3G signals

Is it possible to sniff or record and process GSM 3G signals (from some reciever) given that there is no other signals interrupting etc (the most comfortable conditions) Update (with some supporting ...
9
votes
2answers
1k views

WPA3 announced. Really needed?

It seems Wi-Fi Alliance announced WPA3 for the end of 2018. Anybody knows exactly what is new? features, security improvements, etc... Is it because of Krack attack? I thought patching WPA2 is enough....
9
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3answers
9k views

Block all BotNets and TOR addresses from accessing our site

I've heard that many DOS attacks and general "black hat hacking" attempts occur over the TOR network. Is it possible for me to dynamically block source IP's by their presence in a BotNet or similar ...
9
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3answers
2k views

Is IPv6 with NAT less secure than IPv4?

This is a follow up to a snippet from another answer. There, user Ninefingers writes: (...) only allow outbound connections, ever. Do this in spite of NAT as IPv6 will make those NAT defences ...
9
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3answers
5k views

Risk of configuring MySQL for remote access with a dynamic IP address?

I'm looking to make a MySQL database on a VPS, accessible to my home PC through cPanel. cPanel wants the domain name or IP address of the remote machine. However, with standard DSL, I have a dynamic ...
9
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2answers
1k views

Any advantage to securing WiFi with a PSK, other than to keep out unauthorized

As I understand WiFi with a PSK, such as WPA(2)-PSK or WEP, anyone on the same network can decrypt anyone elses packets because everybody has the same key. In which case, if you are not going to ...