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When dealing with encryption tools (TrueCrypt, Bitlocker and any successors) the passwords are always somewhere in memory. Therefore when there are memory dumps on a hard disk, for example in the pagefile.sys, these passwords remain after a PC crash or abrupt shut down (like for example when someone will steal the comp...
According to https://stackoverflow.com/a/26195101/569976#comment41093099_26195101 "[Using the DNS name as the common name is] deprecated by both the IETF and CA/B Forums, and it should not be done. Instead, the DNS names should be placed in the Subject Alternate Names (SANs)" My question is... where is it deprecated? ...
I understand that a lot of APIs are protected using a (possibly public) API Key, to identify who is making the request, and a secret to hmac the parameters and determine if the client is actually who claims to be. The thing is, if I'm sure the API Key is private and use https: What are the risks of not using a secret ...
My company (health care) went through a PCI audit and needs to solve some major issues. Our branches collect CHD on paper and saves them to a network drive as a pdf that our corp office accesses to enter into Paymentech and charge them ongoing everchanging weekly charges. Obviously, that was flagged, mainly for unencry...
Are there any risks to using Tor browser? Does it make you more prone to being hacked, since a majority of hacker community is using Tor?
According to what I read there are four phases: - Dormant phase - Propagation phase - Triggering phase - Execution phase I however am having trouble finding a chronological order in how these events occur and a scenario. The user downloads or acquires an infected .exe file Would this be considered the dormant phase? ...
How is possible to determine if someone make requests with tools for pentesting? Is there any linux command?
I am referring to confidentiality not integrity. are there any security features that UDP lack compared to TCP? According to this paragraph While TACACS uses UDP port 49, TACACS+ uses TCP port 49 for increased reliability I am not sure if reliability means integrity here or a mixture of confidentiality and integrity...
I'm trying to find out what nmap-commands crash an embedded-system. In the process I can see behaviour that I don't understand: On the system port 80 is open and 79 is closed. nmap -p 79-80 -T5 -A -> system crashes nmap -p 80 -T5 -A -> no crash and normal response It doesn't matter which closed ports I add or remove...
I know about IP spoofing is it the same thing? The question originated from the question Is TCP more secure than UDP?
I am wondering if they are any PCI compliance issues around users of a service sending email with attachments that may or may not contain sensitive information through said service? As an example, if I were to to sign up to a service that lets me generate a document and I send that document to another person through th...
The following quote is from the CompTIA Security+ guide: Single sign-on enhances security by requiring users to use and remember only one set of credentials for authentication. How is that enhancing security ? The way I see it is that it's rather a single point of failure. Isn't it more secure to have multiple diffe...
I am trying to send and encrypt mail using openssl. So far, I figure I should use theese commands: cat ${content} \| \ openssl smime -encrypt -inkey lib/me.crt -aes256 -subject "$titre (cs)" -to someone@hotmail.com lib/MAQUETTE1-me.pem \| \ openssl smime -sign -inkey lib/myroot.key -signer lib/MAQUETTE1-myroot.p...
Inside a shell script I want verify a public RSA file. I want to find a way to check if this file is a genuine public key file, nothing else. What are the ways I can verify this input file to check this is a genuine public key file, not a regular file? I will be using this public key file in the future to validate an i...
I'm writing a Python script to generate custom passwords based on a HMAC. I want the passwords to support various websites requirements so I want to map the HMAC output (ex: hex format) to an array of allowed characters. Let's say I want to map 'fea503e5' to numbers only. The issue is doing it securely, as using modulo...
Quoting from CompTIA Security+ guide The first factor of authentication (something you know, such as password or PIN) is the weakest factor. Why? it makes sense when we say that humans/users are the weakest factor in any system from security point of view as we humans forget, make mistakes and break easily. But it m...
I can see one unknown android device on my network, but it has same host-name as my android device. QUESTION 1.Is this possible that on same network two different devices can have same host-name ? 2.Is someone spoofing my device and accessing my network ? SITUATION 1.I have WPA2-psk security key encryption. 2.Both hav...
Is it more secure to apply updates as soon as they are released, or wait to make sure the updates are not causing problems to the system. It might sound stupid but in the last few years I heard about more than one incident when vendors release updates that suppose to add features (not to fix security issues) which caus...
I understand that Windows DPAPI master keys are encrypted (directly or indirectly) with the user's login password - see e.g. Does DPAPI works if a user hasn't a login password? If I understand that correctly, it means that physical access to the computer isn't enough to get the master key. If I enable fingerprint login...
I am using a local account on my Windows 8 computers rather than logging in with a Microsoft account. I see no reason why Microsoft needs to know my login credentials; it feels intrusive to me and it seems like a one more doorway from which I need to protect. But besides from feels and seems, is a local account actual...
Imagine I have an application which uses a biometric based authentication (such as a fingerprint). It takes its hash and sends it to the server. The server has a copy of the hash and compares the two. Now I hack the server and steal the hash. Now I can bypass the fingerprint test. Moreover, let's say the hash wasn't th...
I have a website that uses Azure Active Directory or Google+ for logging in. I go through an OAuth2 login flow, and the users email along with their tokens are returned to me by their identity service. The users email address is their identity, and foreign resources (tokens, and other things), are stored using the emai...
We all know about how Digital Signing works. I just have some questions about vulnerability risk. At first, As I know, the Signature and the Data are separated and we can split the document into two different parts. So we can change both and then re-join them together. Second, I think In network transfer layer, we have...
Is it safe to store important data in an encrypted access token? For example, instead of storing access tokens in a database, not storing them at all and putting their associated data into them before encryption. As in. I'm setting up an Oauth authentication server. I create an access token by wrapping together the tim...
I have been told in the past that with specialized equipment, passive RFID tags could be read at 1100 feet. This seemed a bit far fetched to me, and sure enough, a quick Google search turned up something closer to 20 or 30 feet. That being said, I know that some of the people who told me this are MUCH smarter (and much...
Got a Surface Pro 3 today and noticed in it's EFI that it's got TPM enabled, "Secure Boot" enabled (unsure what such an umbrella/catch all term actually covers) And then in Windows 8.1, it's got BitLocker turned on I was a little surprised that the OS was able to bootup completely (to user login screen) without any...
I have a practice question here: A business is going to determine the dangers to which it is exposed. What do we call a possible event that can have a disruptive effect on the reliability of information: A) Vulnerability B) Attack C) Risk D) Dependency E) Threat I'm getting E) threat for this question but I am a bi...
I read this but it didn't ask the question I want answered. How is Chase Mobile Deposit Secure? What I want to know is how do they avoid accepting a Photoshopped check? When someone gives me a printed check(which is the majority of checks I get), I could extremely easily take it, change the value on it (including the t...
We have a banking application that allows you to pay your bills (using your savings/checking account) -- including your credit card bills. However our system was set up such that you enter the credit card number that you will be paying the bill for. Is PCI-DSS compliance required for this system even if your payment so...
Imagine we are working in a team of around 5 people. We all install new servers on a monthly base and need to find a better way of storing and sharing the server credentials (offline-location/webadress, root login, db login, ...) somewhere where the whole team can access them, read/write. This location does not have to...
In the RSA key generation steps, what if two entities select a common factor to generate n (i.e. pq1=n1 and pq2=n2) resulting in gcd(n1,n2) <> 1 ? This will lead to a problem that everyone can calculate the p and q, thus breaking this encryption schema: gcd(n1,n2)=p n1/p gives q1 n2/p gives q2 How doe...
I've been working on some security engineering problems and there is no solution provided so if someone can clarify, would be great. From the point of view of security engineering, which is not a potential threat? Users denying that they modified electronic assets in the organization. An earthquake. A person disclos...
I need to encrypt some data and have it decrypted on a later point in time. The data is tied to specific users. I've gathered two possible solutions... 1: The first one is derived from the official docs (example #1 @ http://php.net/manual/en/function.mcrypt-encrypt.php): function encrypt($toEncrypt) { global $key; ...
I want to send a Truecrypt volume through email. Of course, I need to password protect it, and the recipient needs to know the password too. A Diffie-Hellman public key exchange would seem to be the solution. What is the easiest and safest way of doing this? Specific instructions would help.
In the last year or so every other site on the net started showing different kinds of notification that they're using cookies and I should be aware of it. The sheer number of different sites doing this made me abandon the initial good-will-idea and rather think that there has been some kind of legislation forcing sites...
The more I read about TLS, the more I get convinced that the browser is the weakest link in the chain. I know that nobody agrees with me as there are no articles about that in Google, but it looks fairly simply to convince users to use unknown (or malicious) browsers to browse the Internet. Many people download and ins...
I want to know if I can allow uploading all types of scripts and add these rules to a virtual host configuration; so please advise and tell me if there will be some exploits that can be used to bypass this security rules ( if yes please how to block it) Thanks in advance, Maybe this question has been answered earlier ...
As in what OS you use, it's version .. etc. Every time I go to the bank and I get greeted with the ATM in the following photo, this question comes to my mind.. Oh and it's still Windows XP till last week at least
I understand they are an attack on crypto algorithms as implemented on various processors, but how do they work? The online papers are too complex for me to understand.
In my question and answer application, Joe signs up, logs in and adds a question. He then shares the question via email to his trusted friends. How safe is it to provide a link within that app generated email to allow his friends to directly respond to the question without having to register on the site? The key goa...
From what I read here, CSRF tokens from the cookie header cannot be read because of the same-origin policy. Is comparing the CSRF token on the cookie header with the form's hidden element be enough? With this method, the CSRF token implementation eliminates the need of saving the CSRF token on the server; is this a r...
We have an application with a form where user can enter a comment. The form is submitted using AJAX. Values are read also through AJAX and returned by the backend as JSON, and then parsed by JavaScript to present it on the page. This form was vulnerable of XSS attack so we protected the application on the frontend only...
I heard that it is possible to test for zone transfer attacks on a web application using host and dig commands in Linux. How it is done?
I'm a student currently pursuing my Engineering in Computers. I'm planning to put all my knowledge in and try to actually implement something related to security. To be more specific I'm more interested in graphical way to authenticate a person. So before i begin my questioning about core way of actually implementing...
I have been wondering what are the benefits and cons of using an OTP (one time password) versus a keyfile to, for example, decrypt a keepass database, connect to a server via SSH, or other uses. Edit: Also.. which would be more secure?
I want to use the SSL protocol. SSL protocol uses port 443. During the initial handshake does the communication occur on port 80 or does the handshake start on port 443? If not during the initial stage, then when port 443 comes into the picture?
I'm just getting into learning REST and came across this great application that instantly lets me test out requests (Advanced Rest Client). The question arose that since it is an extension to the browser and I had to log my credentials in to run the request, is it safe to use? I see nothing but great reviews for this...
If we have a switch with empty MAC table, and three hosts are connected to it - let's say host A, host B, and host C. Host A sends something to host B, and switch remember on which port is host A, but it doesn't know where the host B is, so it broadcast the entire encapsulated packet (Layer 2, IP, TCP, etc) on all port...
Security Intern here given the assignment to find the IP address of an attacker using IBM's IDS. The event or attack in question is entitled X509_Weak_Signature_Algorithm, and from what I understand, this attack involves exploiting MD5 to generate rogue certificates to compromise our servers. When I go to review an in...
I understand the concept behind a zero knowledge web application where only the user has access to their data. What about a social network where some circles of user have access to that data? Is it possible to have multiple public keys decrypt a "friends" information?
As I was about to make payment for my flight ticket, I noticed something strange with the British Airways website's SSL cert. My browser (Google Chrome) was unable to check whether the certificate has been revoked or not! Here's the exact message: The message from Google Chrome says: The identity of this website has ...
Just for knowledge I want to know how to get the information from the i-frame displayed to the user back to the attacker? Scenario : Suppose You are an attacker and you want to grab the private information of users that is displayed on a web page only to them. So, You find a clickjacking vulnerability on that Web Page ...
On our website, when an invalid PHP session ID is detected, it's logged and regenerated. This invalid session has been logged: n040jl1nujch72tkrmr0uilnl1, s_vi=[CS]v1\|2A19B9B4853135D2-60000109E00013F4[CE] Is that somebody trying to exploit a vulnerability? This is the current way the ID is regenerated // If it's inval...
I am on a trade-off between the use of OpenSSL or NSS in an embedded Linux application that makes use of a TPM (HSM). EDIT: I need a SSH server and Apache using TLS, both using the keys protected by the TPM. I am looking for satisfying the following constraints: Good support of PKCS#11 (at least management of Ellipti...
The german brank credit report service "Schufa" uses a so called "SuperPIN" to enable users to reset their password. This super pin is a permutation of 30 lower and upper case letters and digits and is snail mailed to the user at registration. To reset the password the system selects two positions and requests the char...
You have a website that users log into, and you want to prevent user enumeration. On the login page and the forgotten password page, this can be achieved by careful choice of user messages, but what about the new user registration page? You want to ensure that creating an account for an existing user is impossible, but...
I know that asking how many bits of entropy comprise a strong password is rather like asking the length of a piece of string. But assuming the NSA is not on to you, and that it is hardly worthwhile anyone spending a decade brute forcing your email, then will 80 bits suffice?
I understand that OAUth 2.0 really just relies on SSL to encrypt the contents of the bearer token. However, are there any other best practices one should follow when securing OAuth 2.0? I know you can use a bunch of extra stuff when using HMAC, like nonce, timestamp, etc., but are there any other recommended best pract...
Assuming that we have a "green bar connection" to a website, e.g.: Is an attacker still able to sniff our traffic? How secure is a user from man-in-the-middle attacks when he has established a "green bar connection"?
Some web apps like Facebook and Gmail detect the first time we try to login from a device. Assuming that a browser can't read machine name, and MAC ADDRESS. What kind of variables are they collecting for doing this validation?
Background: A nice Chinese based manufacturer (AllWinner Technology Co.Ltd) produces very useful SoC used boards that often claim to be open source hardware. Question: If need be is there by way of logic and testing a way to find out or at least estimate if there are hardware backdoors on the device. My understanding h...
Normally you are forced to use a corporate proxy. This is necessary for the company to protect against the internet. But a side effect is, that the internet usage of every proxy user can be monitored by the company. This is something nobody wants. In order to protect yourself against the company it is necessary to use ...
I am studying the subject from these notes. However it is not clear what is the difference between "Second Pre-image Resistance" and "Collision Resistance" properties of Cryptographic Hash Functions. As the notes say at "Second Pre-image Resistance", given x1 it is computationally infeasible to deduce x2 such that h(x...
If people use a password to log in to a UNIX server, then it could be forced to expire the password, then they change it. If people use an ssh key and have no passwords, no password expiry, then nothing forces them to change their SSH key regularly. Question: Which solution is more secure? Why do the "howto"'s for ha...
Today I discovered something incredibly stupid - my friend hashes user passwords with sha512 algorithm without a salt. I immediately raised this issue to him but he said he wants to see anyone crack a single password in his database. I told him that without a hash his database is vulnerable to rainbow attack but he sai...
I'm helping my friend with hashing his passwords, and I've a question - Should he use one secret string as salt for hashing or is it better to have each user its own salt for hashing? Consider these three hashes: hash("secretKey777" + password); hash("secretKey777" + username + password); hash(username + password); Wh...
What I have: A large file containing lots of secret, true-random bytes (yes, I'm sure they're not merely pseudo-random). I'll call it F. What I want to do: Tell Linux that it can use this file as an entropy source for /dev/random (each byte should be estimated at a full 8 bits of entropy) What I already know about and ...
My Mac is getting weird redirects with Safari and Chrome, however not with Mozilla Firefox. Since I cannot find software to do malware removal on Apple products or any good information, I am at a loss as to how to proceed after uninstalling and re-installing the affected browsers and deleting all the plugins/extensions...
I am trying to configure the icefloor firewall on OS X 10.9 so as to make sure all traffic will go through VPN. I recently notified that even with "Route all traffic through VPN" option in tunnelblick some connections were made not using utun0 interface. As there is not this option in OpenVPN connect, which I prefer t...
I am very new to MITM attacks and have been faffing around on my home network today.. When sniffing my iPhone trying to connect to some mail accounts I have noticed that it shows a message stating the connection is unsafe, then asks if you want to just continue or close the connection. If continue is pressed it will se...
I am trying to understand the logic behind following vulnerability, I believe this a design flaw not only an implementation. To me the problem with the two-factor authentication service at PayPal is that the server does not distinguish between authentication request coming from the mobile app and the web-app. For that...
Are any other identification information that my wireless card sends to the Wi-Fi network apart from the MAC address ? If so are they changeable? Let's say, for example, that I connect to a Wi-Fi network once and then I change my MAC address to reconnect: can anybody see that I am the same user ?
We have string B and the hashes hash(P+B), hash(P); is it possible for P to be revealed easier using this information than having hash(P) ? What is the difference ? Any links to articles or any kind of information to help me better understand this is really appreciated.
I am developing a secured file sharing project using Java RMI. The files' content has to be secured. The server will store the encrypted files and the client will be able to upload/download/list files (with password authentication). I am new to security and would appreciate any additional security measures I could impl...
We have a webapp that is build to use SSL for certain (but not all) types of requests. The webapp is using multiple subdomains, the number can change. This combination of features makes that the webapp requires a wildcard SSL certificate. The webapp is used by some people, but not by a whole lot of them. We would like ...
The article on Wikipedia doesn't explain how the attacker can authenticate to the remote server using the hash instead of the original password. According to the following article the attack is still possible even with recent versions of MS Windows https://samsclass.info/lulz/pth-8.1.htm Also is this attack limited on...
We host a database for one of our applications on Microsoft SQL Azure. One of our clients was dissatisfied with the fact that TDE is not supported on SQL Azure (and the database is otherwise not encrypted at rest). Their concerns were mostly along the following lines: Data-center employees that have access to the VMs ...
On some sites such as WriteCodeOnline, sprintf, vsprintf and other related formatted string functions are disabled for security reasons: Warning: vsprintf() has been disabled for security reasons on line 1 I'm wondering what these security reasons are. I've already read the Wikipedia article on Uncontrolled format st...
Could someone suggest an optimal ssl cipher configuration for my nginx server that supports both CloudFlare and CloudFront? I have tried a few of the suggestions in other threads, but CloudFront returns errors. Update 1: The relevant content from my current nginx conf is below. I have tried a variety of cipher configur...
Above picture is captured from iOS Security overview at page 25. The path encrypt with public and decrypt with private makes sense. But the other path, encrypt with private and decrypt with public to recreate plain text is something i am not able to understand. If it is just for integrity check, then that should be fi...
Can an internal hard disk (on which Ubuntu or any other OS is installed) that I detached from the PC or laptop (Keeping the OS as it is) and connected to some other PC or machine reveal the info of the PC from which the hard disk was detached? Is there any log file that holds this information?
I am a bit confused about packet decryption of Tor on the client. I understand that if a client sends a request to a web server by using Tor, the request will be encrypted a couple of times, and sent to a Tor relay. The relay will decrypt a layer by using its private key, and when the request reaches to the exit node...
I'm evaluating the security of an Android application and the application is using the XmlPullParser included with Android. I'm having some difficulty getting any common attacks to work, but I want to be sure I haven't missed any possibilities. What are the minimum requirements/features this parser needs to have ena...
I might at some point to invite another person into my software project. I don't mind sharing the code but the data I use is very sensitive. Once he gets hands on both pieces I wont see him again (if you know what I mean).. The server is going to be collocated. He is going to want an admin access to the box remotely. S...
I recently found the ability of attaching files to entries in KeePass 2.0: does KeePass just remember the location of files attached to the entry or does it encrypt the attached files inside the KeePass database somehow?
If you have closed all your ports on your internet protocol, you cannot make a connection to that internet protocol. So how do attackers (DoS or any other means that need a connection) make a connection, when even if you have not closed all your ports, your firewall seems it has. I am saying this because when I port sc...
I am currently developping a platform with a PHP framework for our client. The head of the client's IT department wants us to handle authentication with one database field containing email+password+salt (hashed) so there isn't a plain text email field in this table and the password is more secure (his reasoning). The u...
I was reading an article about log files and referring to apache error log it mentioned that the logfiles should not be writeable by other users. How can this be dangerous? Is there a certain type of vulnerability that I should learn about ?
I have a proxy server in my DMZ that among other tasks has the role of scanning incoming messages - email, SOAP - for viruses. How do I prove to my team leader that it is performing this role on all incoming messages?
I am connected to the internet in the office where I don't want the administrator of the network to find out the contents I check (for example images). First I use a Firefox private browsing window to not leave a trace on the computer. Then I supposed when I search images through SSL protocol (I mean in particular http...
I want to generate a Certificate Signing Request for my server and in order to do so, I first need a secure private key. When I create a private key by using openssl genrsa -des3 -out server.key 2048, I'm asked to provide a passphrase. After doing some research, I found out that not having passphrase is a high security...
Here is an article that should give a little more context (and see my comment on it, same username, for additional info). iOS developers are able to distribute apps outside of the App Store using an Enterprise provisioning profile. This allows apps to be installed even right from Safari without the need for App Store a...
I'm going to print some business cards, and along with my email address I was thinking of putting my PGP ID on it as well. After doing some research I found that using the short ID is not a good idea. What is the best way of doing this - or should I forget about it?
Brussels Airlines allows several payment types, only two of which are free: Maestro and Sofort Banking: The second option was new to me, but direct debit is usually a free and practical way to pay: The request is forwarded to the bank web site, I fill in my details as if I were logging in, and the bank returns me to t...
I want to switch from using LUKS for full disk encryption to TRESOR. TRESOR tries to prevent cold boot attacks by storing the encryption key in the CPU's registers. It uses the kernel's crypto API for things like getting IVs and using a mode like XTS. However, the actual key is requested once the kernel boots and any k...
Comodo certs such as PositiveSSL have a chain length of 4, including two intermediate CA certs. What would be the benefit to them, or to me, of this length chain instead of a chain length of 3 with a single intermediate CA as other providers seem to use? I am aware that it results in a slight increase to the data excha...
Most Wi-Fi security is focussed on blocking authorised access to the network providing a wireless access point; but considering the smorgasbord of background app-to-cloud communication on a mobile phone, connecting to verified Wi-Fi access points is as least as important as SSL/TLS website verification. How, if at all,...
I need to get SSL certificate of some mail servers. I know I need to do execute following steps. Do a DNS mx query on the domain name (dig google.com mx). Use the information to download SSL certificate (openssl s_client -showcerts -connect google.com:443). But I am not sure what information I should pick up from s...
dear security experts: we would like to create a very safe webserver. we are in awe at the sophistication and complexity of many solutions, but they don't apply to us. we are a small shop. by safe, we mean a php or perl based internet-open website that limits the intrusion vulnerability with respect to remote sophis...
Developers are dogmatic on having "invalid username or password" on login screens; our applications should not reveal if somebody is a member given an email address. But there are two other ways our application can reveal a member: the signup page returns a "this email was registered by somebody else" (often this is a...

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