A server is a machine running a software daemon that is generally accessed over a network by other machines.

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NX bit causes segfault on NOP slide?

doing an assignment for university. We have to exec a shell on a remote server. We're told the NX bit is not set, however, when we redirect to our injected code, the server has a segmentation fault. ...
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Using SYN cookies to perform a DOS attack

In my software security class, we had this question: You are the system administrator for a provider that owns a large network (e.g., at least 64,000 IP addresses). Show how you can use SYN ...
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541 views

Server root attack?

Someone in Hungary tried something odd recently: /?_SERVER[DOCUMENT_ROOT]=http://94.199.51.7/readme.txt? This is the partial URL from my log, showing the page they went to. They gave my site's URL ...
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Can email be encrypted before it reaches the mail server? If not, is there something that would allow something like this that's being worked on?

I was thinking about hosting my own email (own email server) instead of using Gmail. But then I realized I could never host my email on a server where I'm also hosting Wordpress. That is because I ...
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1answer
73 views

Will installing a Graphical User Interface in a server be a security problem?

I'm not a CLI-lover, sometimes I prefer to do some tasks in a server using a GUI rather than using the CLI (it speeds up my work), but I don't know if installing a GUI and accessing it using VNC and ...
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272 views

TLS server key: possible to sign another TLS server key?

If I have a valid (verifiable) certificate C_K_s that links the server key K_s to "www.example.com", is it possible to : use K_s to sign K_d, and let S_K_d be this signature use K_d as the TLS ...
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Cryptolocker: can servers be protected?

I'm IT in a small company. The network is about as ancient as most of the staff (at 30, I'm the company's youngest), and the staff also is notorious for spreading viruses around the network despite ...
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What are the pros and cons of using fail2ban when using SSH key auth? [closed]

I've just bought a new dedicated server. Should I install fail2ban if I am only using SSH keys to login? What else does fail2ban protect? What are the advantages and disadvantages of fail2ban? Is ...
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952 views

Securing server to server http communication

We are trying to come up with a scheme to secure http communication between our internal servers. Are there any good established schemes out there? The requirements we have are: The clients and ...
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310 views

Does using NAT-T for L2TP / IPsec VPN pose a realistic security risk?

I'm working on upgrading an old Windows RAS server that hosts PPTP VPN. I want to move to a L2TP/IPsec VPN. Due to the firewall appliance we use, the VPN server has to be behind a NAT. This means ...
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59 views

How do I protect the stored clients' public keys on a server?

I'm learning about security at the moment, and I want to store my clients' public keys on the server to facilitate distributing and managing those keys, my question is what are the possible ways to ...
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119 views

Investigating a possible rogue DNS Server (maybe DNSChanger)

One of the users of our RouterCheck tool was complaining about random popups containing ads in Spanish and Russian. Upon investigation, we found that the DNS settings on his router were changed to ...
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Authy: Does multi-device mode imply that all keys are stored on their servers?

My understanding is that if you use Authy, without backups/multi-device options, none of your account keys are stored on their servers. It all resides on your single device. Ie, even if Authy ...
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2answers
1k views

How does a firewall help to protect a server?

Since a potential attacker will exploit the services that are already open to public by firewall rules, how will a firewall help to protect my server from attackers?
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234 views

How To Prove That Client Side Javascript Is Secure?

Imagine that you have a web application that encrypts the user's data, such as a note or spreadsheet, on both the server and client. The normal process for a user using this web application is ...
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117 views

Is a newly installed server with no services running (but connected to the web) at risk?

A new server has just been installed but literally has nothing else running on it, no services setup to SSH in or anything yet (it's a Linux server). However, it is hooked up to the web so I can ...
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478 views

Does Ubuntu Server have a “phone home” feature?

I've heard that Ubuntu has some sort of "phone home" system that is enabled by default. The kind of stuff that passes along performance information and that type of things to Canonical. I don't know ...
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524 views

Disable local/KVM access on a Linux VPS (allow only SSH)

Friends of mine have previously had issues with VPS security. The security was no fault of the operating system/services themselves, but mainly due to the "Control Panel" that gets forced upon you ...
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136 views

How to keep logs safe from attackers?

I have a Linux server equipped with some security apparatus to prevent unauthorized access. Hopefully, this will prevent intrusions, but the possibility always exists. Naturally I keep logs so that ...
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3k views

Using Window Servers 2003 after security updates are discontinued

Let's say that Microsoft has stopped supporting Windows Server 2003 now so there is no any security updates and I use that system for Domain Controller (Windows XP/7 Professional Clients) and File ...
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3answers
673 views

Error message in Apache logs shows /bin/bash and wget

I am wondering if my server is compromised or not I just looked at my log and seen the following line in there [Thu May 14 09:10:42.587255 2015] [autoindex:error] [pid 3422] [client ...
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Disabling SSL v2 and weak ciphers on client PC's

Is it a requirement to also disable SSL v2 and weak ciphers on client PC's? I have seen quite a few posts for disabling them on servers, but nothing about a regular client PC, say, running Windows XP ...
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What's the best way to secure inter-server communication for cloud servers?

I'm looking for best-practices or suggestions to secure inter-server communications between VPSs. Should I just run all traffic through SSH? What about HTTP Traffic via something like mongo? ...
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Server Certification Processes

We are considering a certification process for new internal server builds before they are allowed to be placed into production. That is, the system administration team will send the server up to the ...
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53 views

Restrict user from executing shell commands using PHP

Let's say that i have shared hosting and i want to secure that place, from executing shell commands. I'v installed suphp, so that users can execute PHP separately. I also did some other things in ...
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126 views

Where to start , secure an AWS Ubuntu 14.04 [closed]

Ok so this is probably a basic question but I would like to expand my knowledge. I have created an AWS Ubuntu EC2 server. I am running software on the server that provides 2 services , firstly a ...
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93 views

Redeploying multiple Secure sites on a single server

This may not be a great site for this question. I basically have approximately 10 VPS instances running a secured website each, each with their own SSH connection to a hosted Database. What I'm ...
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OpenVPN: Storage location and creation of keys/certificates?

I am re-setting up some OpenVPN infrastructure to be more secure than the original and wanted some guidance. It's noted that the best security policy is to keep the Certificate Authority (CA) offline ...
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2answers
98 views

Cybersecurity Server Stack references

I hear a lot of best practices saying that you should have 2 vSphere server stacks: One for Production One for Cybersecurity For example, your enterprise might have a vSphere environment stack that ...
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103 views

What is a decoy-server?

I see that the term "decoy-server" is often used but I am not able to find a more formal definition for it. Can someone help? E.g ...
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45 views

Prevent snapshots of VPS

Pretend I have a server. Is there anyway to prevent (or make more difficult) the administrator from taking snapshots? Feel free to give me a software way, or suggest if I should change server types; ...
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2answers
205 views

Is VM per service a reasonable server security model?

Let's say I am hosting several services on my server, for instance, email and a web page. I am concerned that the web server software may have unknown vulnerabilities in it, which will allow an ...
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199 views

Updating stored, encrypted containers on a server

My scenario is this -- I want to store an encrypted container on a network server. This encrypted container should be accessible to others to download and decrypt/mount locally provided they have the ...
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Distinct databases with the same Kerberos Authentication server

Should two deployed applications within a private network requiring distinct databases (for storing their own users credentials) require distinct Authentication servers (implementing Kerberos)? Or is ...
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How to protect my server from continous login attempts (Ubuntu)

This is the log of my server: Mar 25 16:49:51 f4arelay sshd[10831]: input_userauth_request: invalid user git [preauth] Mar 25 16:49:51 f4arelay sshd[10831]: pam_unix(sshd:auth): check pass; user ...
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2answers
104 views

Physical protection of your servers?

Here is a scenario. You are a small startup company that makes a video game. In your video game, you can exchange money for items. You are not dealing with the credit card/debit card directly but ...
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2answers
398 views

Are there any logic-bombs that execute when the file is deleted?

I want to delete a suspected malicious file from a server. For the purposes of this question assume that the infected machine is Windows Server 2003 or later. Is there any risk in deleting such a ...
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Protecting IP on a remote server

Apologies in advance if this question is a bit vague. I just joined a stock trading group. A guy set up a server for me, and it's racked in their building. I ssh into it, and run my algo remotely ...
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1answer
55 views

Is it a good practice to forbid ip access to port 80?

I see some sites have blocked there port 80 (or 443) to be accessed by IP. When you access by IP, An Nginx forbidden page shows up (with there OS version). My question is does it affect any side of ...
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2answers
98 views

Is using a sqlite with random name file secure?

As you know, SQLite have no security mechanism. My question is if i change the database file into some random name like '22OYIz23tmpyesTcMVFmw1tquFxzCIQD.sqlite' can someone exploit my database and ...
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634 views

How to find out the email host of a vanity email address?

Assuming a person gets his own domain address, say, theperson.com. He then goes on to create a vanity email address with that domain. e.g. me@theperson.com. me@theperson.com may be hosted by the ...
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2answers
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Is IP whitelist sufficient to protect a server? [closed]

I am currently using a server 1 managing incoming traffic from users and a server 2 managing database requests from server 2. Both servers are accesible via Internet. Would IP whitelisting be a ...
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3answers
252 views

How to regain access to the server?

I have a Debian server with KVM available 24/7. It was recently broken into and its root password changed. My hosting provider has restored my access and helped me change the password. But in the ...
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1answer
90 views

Can data coming into my UDP server be sniffed?

I have made a small tracking device. I am trying to reduce the data overhead as much as possible to make the device very cheap to run. We are working on the basis that 1MB = £0.01 (the data price at ...
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1answer
91 views

How do hackers get into servers? [closed]

I am a web developer. I've checked How does hacking work? and I know all of the things described in the most upvoted post. However, I can't understand how do hackers get into servers when the website ...
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2answers
399 views

Web Service Security Checklist - Tracing and Debugging

I have been reading this security checklist about web service design: http://msdn.microsoft.com/en-us/library/ff648304.aspx One of the suggestions is that you should disable the following in ...
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4answers
254 views

Why should I log successful log-ins to my server?

I was arguing with a friend about logs in user logins. I think that logs means a big audit source for IT audit professionals. Why should I log successful log-ins to my server? It's so important log ...
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1answer
370 views

Security on dedicated lines

Is it safe for a company not to use any encryption on customer's data when it is transferred between data centers on dedicated lines? By customer data I don't mean passowrds/credit card info. Just ...
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1answer
658 views

storage of client credential on OAuth2 server

I'm developing an API and used a recommended implementation of OAuth2 protocol: PHP OAuth2 Server. This library stores client ID and client secret as plain text in a database table. Note that I ...
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1answer
202 views

What is attacker trying to do with my server?

Some is trying to access this link (and similar ones) frequently in my site: http://example.com/upload/RS=%5EADAJVxZ5NB.GMTgFV3EMEJX3sN22Jw- Note that my server doesn't have an upload folder inside ...