Network Security - securing network infrastructure and connections

learn more… | top users | synonyms

9
votes
2answers
913 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?
9
votes
2answers
496 views

How does the Copyright Alert System work? Who has implemented it?

Some ISPs are participating in a Copyright Alert System that notifies content authors of violations of their copyright. I'm concerned how this oversight relates to my private traffic, and what laws ...
9
votes
4answers
664 views

A firewall without any extra features [closed]

I have Kaspersky Internet Security (KIS) installed on my system. I always keep it disabled, yet using a few practices, I kept my system virus free for years: I disabled autorun using these tricks; I ...
8
votes
2answers
3k 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 ...
8
votes
3answers
406 views

Is secure Caller ID possible for SIP / VOIP?

Is there any way (standard, proposed or draft) that will allow for secure Caller ID over SIP / VOIP networks? I have constantly heard that Caller ID is insecure when used over these services. Can ...
8
votes
4answers
2k 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 ...
8
votes
4answers
5k views

Why is WPA Enterprise more secure than WPA2?

In personal mode WPA2 is more secure than WPA. However, I have read that WPA Enterprise provides stronger security than WPA2 and I am unsure exactly how this is achieved.
8
votes
4answers
2k 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 ...
8
votes
2answers
298 views

What is secure enough for web applications?

we intend to build a network in a small health center with No Internet Access it is expected to have 30 terminal machines, all machines will use an electronic medical record web application we want ...
8
votes
4answers
3k views

Is NTP vulnerable to DNS poisoning or spoofing attacks?

Scenario: Attacker somehow compromises the DNS lookup for the NTP server used by the victim (a web application) Victim sends DNS request for e.g. ntp.pool.org, which is responded to by attacker to ...
8
votes
7answers
2k views

What security implications are there for allowing outbound SSH traffic?

My school currently blocks outbound SSH traffic. Users inside the network cannot use Port 22, and attempting to make an SSH connection over another port is also blocked. (I'm assuming the firewall ...
8
votes
4answers
481 views

CAM table attack in 2011?

Today's switches are vulnerable to CAM Table attack? https://secure.wikimedia.org/wikipedia/en/wiki/CAM_Table
8
votes
1answer
423 views

Is it possible to recognise and prevent MitM attacks on devices which use self-signed SSL certs?

I use both Linux and Windows at work on a large enterprise LAN. The majority of the network configuration is out of my reach. Certain SaaS applications that are hosted locally on the enterprise LAN, ...
8
votes
3answers
337 views

Securing a LAN without Physical Security

I've got an interesting dilemma. I have a large (50+ users) office that is going to be on the campus of a local university. The purpose is to foster collaboration, etc, but the open environment is ...
8
votes
1answer
316 views

Is the system bios and network card protected by the OS firewall?

My question arises from trying to understand new types of spyware that target the system bios and/or network card. Is the system bios and ethernet card both protected by an OS firewall set to deny ...
8
votes
2answers
206 views

Retaining institutional knowledge of a complex infrastructure (checkpoint, juniper, etc)

In the next month my functions will be expanded to include IT security (firewalls, VPN, PKI) in a big complex infrastructure. Can I ask you for advice on how-to be well prepared for it? What sorts of ...
8
votes
1answer
200 views

Are multiple network interface still recommended in a virtualized world?

Before the virtualization era, it was recommended to have several network card on a physical server : 1 for production dedicated network (only application's stream like http, SQL*NET, ...) 1 for ...
8
votes
1answer
12k views

TCP Peer unexpectedly shrunk window messages in dmesg log

We get quite few messages like these in our dmesg log on various servers: TCP: Peer 0000:0000:0000:0000:0000:ffff:d431:5861:56369/80 unexpectedly shrunk window 2522304441:2522312601 (repaired) TCP: ...
8
votes
1answer
721 views

Spoofed IPv4 and IPv6 addresses over the internet

I have a few questions regarding IPv4 and IPv6 spoofing. Might as well just list them to be concise: What's the usual routing policy for ISPs' routers in regards to spoofed source addresses? i.e. if ...
8
votes
1answer
1k views

What's are the advantages of L2TP/IPSEC over plain IPSEC?

As the title says really, my firewall (Sonicwall) can do either IPSEC or L2TP/IPSEC for VPN connections. One advantage of L2TP/IPSEC I can see is that the client computer get allocated it's own IP ...
8
votes
2answers
1k 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 ...
8
votes
1answer
226 views

What is the security vunerability in this scenario?

I saw this question: Suppose a university with address block 12.1.0.0/16 has a link connected to AT&T, where the AT&T router forwards packets destined to 12.1.0.0/16 to the university ...
8
votes
1answer
270 views

Is Chinese great firewall white or black list based? [closed]

Is a new website blocked by default in China ? I just put online a new website dedicated to chinese people (a working days calculator in China, nothing subversive indeed). However a friend of a ...
8
votes
1answer
153 views

Long running SMTP session

I recently noticed an SMTP session on my server which started when a remote host connected but never seemed to result in any emails being delivered. I could see that it was probably a SPAM site and so ...
8
votes
2answers
196 views

Can you tell if an attack is successful by looking at IPS logs?

In my organization, we have an IPS behind a firewall. Each time a security event is triggered, I am left to wonder if the attack is really successful. For events that are set to drop in inline, we can ...
8
votes
2answers
377 views

How do you Secure VOIP in a large organization

As part of a large organization looking to implement VoIP, to get on the bandwagon of savings and converged network focus, I'm being asked to look at the security concerns to develop a policy to help ...
8
votes
2answers
191 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 ...
8
votes
2answers
426 views

How to implement secure device identification in a for-pay wifi router to prevent usage fraud?

After reading this question about how for-pay wifi routers identify specific devices it got me thinking about what a secure alternative might be. I know that certain research has focused on ...
8
votes
3answers
8k views

How to best set up public WiFi without giving access to the rest of my network?

For reference, this is just for my home network. Anyway, I have quite a few of my neighbors ask me to share my internet with them. I'd really like to eliminate this "here's the password" portion ...
7
votes
6answers
241 views

Why shouldn't I run other applications on a Firewall?

If I want to use Ubuntu 11.04 as a Firewall in SOHO environment, then I just can't figure out what is the bad thing about installing GUI on it (e.g.: XFCE)? The only opened port to the world (wan ...
7
votes
5answers
4k views

Can I block based on Mac Address?

Incase of dynamic IP's the hacker can work around 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 users ...
7
votes
8answers
629 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 ...
7
votes
2answers
2k views

Using RSA with 3DES instead of plain 3DES. Does it make sense?

I have a large legacy code. Currently it is using 3DES encryption for a network based application. It encrypts data packets with a main key. This key is used to encrypt and decrypt (symmetrical). And ...
7
votes
2answers
215 views

What to add to a repeating security checklist?

I work in a smallish company (100-200 computers and a handful of servers) and I am trying to come up with a checklist of things to check at a regular basis, such as weekly, monthly, etc. We use ...
7
votes
5answers
4k views

How to detect hosts running in virtual machines with nmap?

I have to determine if a given subnet has virtual hosts. Are there any ideas about what switches to use?
7
votes
2answers
1k views

IIS IP Adress Restriction - can I rely on it online?

I've been told that I might have more luck posting here than on Stack Exchange, so here goes: I'm looking for a way to lock down a 3rd party application in IIS. It's a web service, so there's no ...
7
votes
3answers
2k 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 ...
7
votes
4answers
2k views

Security Services on Edge Router vs. Standard Firewall

If I can run a site to site VPN, NAT & Reflexive ACLs on a edge router (plus normal routing functions), what would be the use of running a stock firewall behind it? For instance, Core Switch --> ...
7
votes
1answer
320 views

different portscan tools give different results

I have different results as of my open TCP ports. When using nmap -sS 127.0.0.1, I get some 5 usual open ports, but when using osx built-in tool as stroke, I get those 5 ports plus 5 extra ports. How ...
7
votes
3answers
2k 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 ...
7
votes
2answers
7k 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 ...
7
votes
3answers
476 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 ...
7
votes
3answers
2k views

Encryption on mobile phone - myth?

Well, about six months ago I had pleasure to meet Harald Welte and when he talked about m-banking (banking via smartphones) he said that the most people thing it's safe while, in fact, mobile ...
7
votes
6answers
1k 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 ...
7
votes
2answers
694 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 ...
7
votes
3answers
763 views

Why don't wifi managers remember mac addresses for hotspots to defeat the jasager attack?

So I just learned about the jasager attack, via the wifi pineapple and it struck me immediately that it wouldn't work at all if network managers (privately) associated MAC addresses with hotspots and ...
7
votes
4answers
780 views

Verify Mac firmware is not hacked…how to do?

I have a late model Mac computer. I allowed someone to plug in a USB drive, and my network activity changed afterwards. Normally, Little Snitch will report every app that uses the internet. Every ...
7
votes
1answer
144 views

Deanonymizing users by introducing structured delays to the network?

Here is a scheme for deanonymizing a user that I've been thinking about, just out of curiosity. I tried searching for it but didn't find much. Does this technique have a name? Are there any papers or ...
7
votes
3answers
2k views

Alternative approaches to using DMZ for securing communication to and from external web server outside firewall

I am a software developer with little network security knowledge and almost no knowledge of the current network architecture for the environment I work in. If I had any, I still would not want to ...
7
votes
5answers
971 views

Creating tunnel with most ports closed?

How can I create a proxy tunnel from a network that has all ports but port 80 closed? I guess I'd have to bind SSH on my server to port 80, but would that introduce problems to my home network since ...