instruction stringlengths 24 29.9k |
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According to process of authenticating a server certificate:
What's keeping a malicious server to fill up a valid server certificate since it knows all the things:
Forged Server public key (man in the middle public key instead of actual server public key)
Certificate serial number. (actual server)
certificate vali... |
I have 3 CentOS server configured for my applications. Recently I recognized that there is so many attacks to my servers. I have so many logs about attempt to login to my servers using sshd from unknown IPs.
This is some part of my secure log:
May 25 03:45:03 mail sshd[22291]: Invalid user user from 42.121.117.150
May ... |
I already know that some concerns of lack of security in TCP/IP are that TCP/IP does not support strong authentication of packets and no encryption of packets. What other weaknesses are there in the TCP/IP regarding security concerns?
|
The enterprise where I work has a proxy server that traces and filters our web activities. Employees claim that they can know the links that we visited and see the content of HTTP web sites, but they can't see the content of HTTPS secured web sites because the content would be encrypted by the server. I don't share the... |
If I do not define any range (or if the range is large like a hundreds of ports), Nmap is returning ports as opened. However, if I put a smaller range or just scan a specific port, it says it's closed.
For example:
nmap -sV
1110/tcp open nfsd-status?
1111/tcp open lmsocialserver?
1112/tcp open msql?
1113... |
I recently discovered a way to bypass a commonly used security seal system, requiring no special equipment and taking only a matter of seconds. I feel obliged to disclose this, so as to avoid the possibility of users of that seal system harbouring a false sense of security.
I would use CERT's Vulnerability Reporting Fo... |
I am an admin of an immigration forum. Security is my job One and protecting our members's info is my highest priority. Recently, I discover that there are 3 members who have posted from the same IP addresse and the same iPhone browser info. My questions,
Is it possible that different people would have the same IP ad... |
Say I have previously created a private/public key combination, and decided at the time to not protect the private key with a password. If I later decide to "beef up" security and use a password-protected private key instead, would I need to generate a new private/public key pair, or can I simply add a password to my e... |
I wish to set up SSL/TLS for my site. How can I do this on my own without using a certificate authority.
The site will be accessed only via certain machines so I can easily install the public certificates on their browsers.
|
There is a web application which contains a search function. When I search for aaaaaaaaxss I get this:
<meta property="the:property" content="100 Results for aaaaaaaaxss (Page 1)" />
It strips the < and > characters but not double quotes. However, since I cannot get rid of the other input, I cannot use 1;javascript:ale... |
I've been reading about SSL/TLS and I was surprised when I saw the amount SSL/TLS implementations that exist. wikipedia.
So, is there really a need for all these different implementations?
Wouldn't it be cheaper, more productive and faster just to mantain one implementation like OpenSSL?
|
I have two questions regarding Tor (onion routing).
How do I receive responds from a server when I use onion routing, I've read that, the last node(exit node) will use the same path I used but in the reverse order, but that means that
the last node will know who I am. It was never clear anywhere but I guess that the ex... |
Assumption used: all password that I've used have been salted with some random elements before hashed and stored somewhere in their database.
If my previous password exists only as salted-hashes in their database,then when I:
trying to use a previous password during the password reset phase (as I type it into the new p... |
I have an ASP.NET web application which uses HTTPS and XML based request-response. It seems a user's session cookie can be retrieved via XSS, if the request/response is intercepted and malicious JavaScript code is added as a payload.
Since it is an XML based request-response, the payload has to be HTML encoded. Here is... |
I have been looking for an operational security guide for generating one's asymmetric key pair for (Open)PGP. I have found plenty of technical guides for how to use GnuPG to generate RSA key-pairs, for example, but not much organized content of how to do so securely.
The use case is an average user wishing to use asym... |
I am doing an HMAC of some cipher-text, IV and encryption algorithm. Right now I am using a hard-coded key that is known to both sender and receiver. I was wondering if the key should be changed once in a while? If it does, how would I synchronize the keys with the receiver? Is sending the HMAC key in plain-text a very... |
If I was able to view any page on a website as localhost using SSRF, what files should I check for? I checked to see if I could view robots.txt normally, and I couldn't, but using SSRF, I was able to. What other files are typical on websites that are normally hidden to the public, but would be visible on the localhost?... |
How can I block websites in Firefox from viewing my browsing history within my browser cache? For example; I've done some Google searches that Amazon is now starting to use to target advertise; the issue here is that Amazon is able to view my history for Google; how can I prevent this at the browser level?
|
It is asked in stackoverflow, but I suppose maybe it is more suitable to ask here.
It is said that openssl are widely used, however, as far as I know, the most popular browsers seem not use openssl, instead, they use other SSL libraries like:
NSS (for all firefox and chrome in Linux)
SChannel (for browsers in Windows)... |
Wordfence reports the following visitor:
An unknown location at IP 0.0.0.0 visited
4 hours 45 mins ago IP: 0.0.0.0
Browser: Baiduspider version 2.0
Mozilla/5.0 (compatible; Baiduspider/2.0; +http://www.baidu.com/search/spider.html)
An unknown location at IP 0.0.0.0 visited
4 hours 45 mins ago IP: 0.0.0.0
Browser... |
This is something which I have been wondering and trying to find an answer for, but yet to come even remotely to one.
Why do you need a 4096-bit DSA/El-Gamal key when AES uses only 256-bit keys?
|
I've lost my master password. Not all is lost as I know the original word that generated the password: It was generated by a random case switching for consonants and random vocal to numbers. For instance: a and A become 4.
I'm searching online for list generators that takes the seed word and generates permutations as I... |
One of my friends told me that running tor in a virtual machine Linux and then passing it through a proxy on the underlying Windows would provide in his words great security. Is this true?
|
I have set up an SSH server to accept only login using codes generated by Google Authenticator (I have disabled all other forms of authentication on that port). After having rebooted my remote machine, it keeps giving me the Access Denied error after having entered the code on the authenticator app. It has been working... |
Given that an attacker only knows the public key and cipher text, why is it difficult to decrpyt the message ? If the knows the N value will he be able to decrypt it ?
|
By several REST clients the credentials are sent with every request through custom HTTP authorization headers to the REST service. Is there a way to force file download in the browser when accessing files stored in the REST service, is protected with this kind of authentication?
Force file download: Content-Disposition... |
There are well known attacks to WPA by capturing handshake and running offline hashcracking against it. Also there are tools to exploit vulnerability in WPS to get the PIN. My question is why WPS handshake (if it is called handshake) cannot be captured and the PIN revealed. It seems impossible otherwise obviously someo... |
Did anyone successfully exploit CVE-2010-4478 in the past? This is insufficient validation of the J-PAKE public key parameters in OpenSSH up to 5.6.
I'm dealing with a vulnerable machine running OpenSSH 5.1 p1. I need to get a flag but in order to do so, first I need access to the server. I found the vulnerability of j... |
I need some help in understanding the security risks if I want to use OAuth 2.0 (Facebook, Twitter and G+) as standard login provider for an E-Commerce site. Keeping in mind that I will not be saving Credit Card information on the site or in any of the data stores. I would be utilising services such as PayPal (And Simi... |
My boss proposed me to code from home on the their machines via internet, in two possible ways:
I would connect to their computer and work on their machine, as if I was in front of the computer(from what he said the method used in this case would not be a VNC but something different)
Via SVN
My concern is all about t... |
I've bought a new phone, where one of its products can be activated by receiving a phone call. If someone uses a spoofed SIM card - with a number I recognize - I'll likely answer the call.
Are there ways to circumvent this? I'm currently using a phone for data only, and another for calls and SMS: This leaves my calls a... |
Google recommends using a 130-bit cryptographically-secure random number as an anti-forgery token.
Why do we need so many bits? If an attacker decides to mount a brute-force attack, wouldn't you be able to detect and lock them out after a few attempts? With as little as 30-bits, you've got 1 million possible tokens for... |
Note: Original question asked at https://stackoverflow.com/questions/24012390/is-this-token-based-web-service-secure but here seems to be the right place for it.
The company that I current work for has an internal application, it provides some RESTful (sort of, just a collection of URLs) APIs. To access the APIs outsi... |
Apple has just announced iOS 8. The new version appears to be more extensible than previous versions, and one of the new possiblities is to allow developers to develop custom keyboards, different than the system's default.
Android has had this feature for quite some time. On Android, those keyboards are known as a poss... |
I'm developing a personal project and one part of the project is a php website, hosted at hostinger as a free plan, that allow clients to ping to it and stores the WAN IP and the NAT IP of them.
They can ping to the web page just making a GET request to:
mywebsite/ping.php?ip=XXX.XXX.XXX.XXX&description=USERNAME
where... |
If there is an employee uses the internet through an internal proxy in his company, and he use a paid VPN service to browse safely, can IT side be able to monitor his behavior?
|
I have been reading about SpyProxy. Can someone explain me this phrase I found in the article ? Here it is: We monitor the guest OS and browser through “triggers” installed to look for sandbox violations. I am looking to understand what is the nature of the triggers they may install in the Virtual Machine ? I appreciat... |
I've been wondering about this scenario for a while but I cannot fully understand how it works.
Say I am sitting in a cafe on my laptop with wireshark, the cafe has an open WiFi connection. Is it possible for my laptop to become a wireless access point (i will call it something similar to the cafe router) but then redi... |
After reading about BitCoins, I can't help but contemplate the idea of the a government withdrawing paper money and bringing all currency transactions digital, via a bitcoin-like method where every unit (1 cent, US, for example) has an id and an owner.
This would theoretically help eliminate theft, tax evasion, money ... |
I know that hashing is a one way function and encrypted messages could be retrieved if you know the corresponding key to which you encrypted the message. Other than the ability to retrieve, what advantages/disadvantages are there in hashing over encryption?
|
Now, I understand this might not be the right place to post about Acunetix but I'm searching my site for any exploits and a couple of SQL Injection exploits have shown up on a /Profile page, how would I be able to see the issue through my own browser (i.e. See the SQL error through my own browser instead of the Acuneti... |
What are the security implications of executing external processes using Java ProcessBuilder/Process? For example:
Runtime rt = Runtime.getRuntime();
Process proc = rt.exec("processExecutable");
InputStream is = proc.getInputStream();
int c;
while ((c = is.read()) != -1) {
System.out.print((char) c);
}
int exitVal = ... |
I'm a little bit confused about the contents of Finished Message used during Handshake Protocol. In particular, this message (clientside) contains the connection-id originally sent from the server and it also contains a hash value derived from all previous handshake message and master secret.
So this message is encrypt... |
I see a lot of materials in Internet about this technique. I'm not really interested in malwares, but I'm curious when you change bytes to an exe with other bytes, wouldn't this corrupt the exe? I can give example videos if somebody didn't understand my question.
|
The AES algorithm and asymmetric encryption use multiple key lengths that affect the strength on the key used. But, how does the key size and algorithm strength affect encryption strength?
|
i'm a newbie and i'm having a problem that i can't find it by google.
I'm researching abbout DDoS detecting method now. As we can see that nowadays people often analyze networking traffic from router by a computer inside LAN.
But i see that there're some companies which have services for traffic monitoring and packet ... |
From Beginning Cryptography with Java - chapter 4, digital signatures:
Signatures are created using the RSA algorithm by applying the RSA
algorithm using the private key and then distributing the result as
the signature. Because of the way the RSA algorithm works, this means
the signature can be decrypted using ... |
Consider a user who wants to use a password manager for their banking passwords. Advice from banks usually says they should never write down their password. The user would be concerned about going against that advice, as it could mean their bank would refuse to accept liability for any fraud that may occur on their acc... |
Consider the problem of hardening an existing, database-backed web application, to detect attacks and stop them where possible.
It seems like one plausible approach might be to build an intrusion detection system that has observability at two points: (a) at the web server level (e.g., to observe the page being executed... |
Are heap spray exploits possible, if the process we're attacking is a 64-bit process?
Naively, it seems like the 64-bit address makes it difficult to mount a heap spray: to fill all (or a significant fraction) of virtual memory, you'd need to spray an absolutely ridiculous amount of data into the heap. I realize that ... |
In SSL/TLS handshake, a nonce is always sent by the client to server and vice versa.
The nonce basically consists of a random number and unix timestamp. Why do we need the unix timestamp?
As the nonce is always a random number, how does this protect from replay attack by a man-in-the-middle? Being a random thing, same... |
So the first reason we give to encrypt content is to prevent against a man in the middle sniffing all data. That is the reason ssh is used and not telnet for example. But in today's networks where there are really no hubs and all switches how easy and how prevalent are packet sniffing attacks?
What exactly needs to be... |
Are there cases where a serious drive-by download attack could crash the operating system or the browser ?
|
How safe is a hybrid mobile application developed using a GET Web service over HTTPS?
What are the pros and cons of using it and how safe is POST over HTTPS?
|
My office has about 20 PCs running Windows XP. I got a message saying that Microsoft is no longer releasing any security patches for Windows XP. However, we find that XP is very convenient for our work. Please suggest some possible ways to keep Using Windows XP for my PCs without any risk.
|
We have a long-standing ActiveSync device policy that requires an unlock code for all phones that use corporate email.
It seems that iPhones with "swipe to unlock" and Android phones with similar technology process this policy different: iPhones allow a swipe to unlock feature, while Android does not.
Is "swipe to unl... |
I'm implementing a way for users to share messages with other users. All users and admin-users have a unique key pair. A message can be sent from one user to multiple users.
Admin-users, who always have access to all messages, in case a user loses his password, and then makes a new password (with a forgot-password emai... |
I have a classic ModSecurity configuration (apt-get...)
SecRuleEngine Off
SecPcreMatchLimit 1000
SecPcreMatchLimitRecursion 1000
SecAction "phase:1,t:none,nolog,pass, \
setvar:'tx.allowed_methods=GET HEAD POST OPTIONS', \
setvar:'tx.allowed_request_content_type=application/x-www-form-urlencoded multipart/form-data te... |
If someone is able to post on the forum of my website links to executable files (malware) hosted on remote websites: can we say that my website suffers from a security hole ?
|
If I click on the little lock icon in Chrome it says that the site in question is using TLS v1. I also checked using openssl and was able to hit the site using TLS1, SSL2 and SSL3. From what I understand SSL2 is not secure. Based on this, it appears that the site could be hit using any of the three.
What determines ... |
There are multiple gift card reseller sites that buy your gift cards and resell them at discounted price. I was wondering how these sites prevent sellers from reusing the pin and card number after it has been sold (you can use the pin and card numbers online, or even at the store without the physical card).
|
I am 17 years old and my ultimate job goal is a cyber security professional. I have been extensively studying TCP/IP, along with all other subjects in the CompTIA Network+ certification which I hope to obtain soon. I'm very familiar with tools such as OpenVAS, Wireshark, nmap, ect and I'm currently learning Python, and... |
According to https://www.owasp.org/index.php/Insufficient_Session-ID_Length:
Assuming that the session identifiers are being generated using a good source of random numbers, we will estimate the number of bits of entropy in a session identifier to be half the total number of bits in the session identifier.
How does o... |
I've heard a TON of vague info on Gameover Zeus recently. One detail I can't seem to find is if it affects OSX?
when I say I can't find it I mean from a credible source. I've found loads of people on forums saying the classic "Macs cant get viruses", but not any hard facts..
|
I really want to prove myself (to my parents) by winning a proper bug bounty
How should I best prepare for this and go about actually finding bugs?
Edit So can anyone give some web sites which I could read that would help me understand better how to win, and what free training materials are useful? I'm working through... |
I'm wondering if anyone has previously proposed, evaluated, or deployed the following measure to harden systems against heap-based buffer overruns: basically, stack canaries, but applied before function pointers in objects stored in the heap rather than before return addresses stored in the stack.
Consider a struct lik... |
Is it possible to write a snort rule that match on 2 different flows?
For instance on a communication from host-a <--> host-b that happen at the same time as a communication on host-a <--> host-c ?
|
On my Linux machine (Alice), I am setting up a service account with an rsync cron job that will synchronise some files with a remote host (Bob). Obviously, I would want to make the rsync secure by using SSH with a keypair.
So my question is: is there any point in passphrase-protecting the private key?
If I passphrase-p... |
I'm trying to set secure Trusted Platform Module (TPM) passwords on a network and would like to set it to the maximum length possible.
How long can the TPM's password be? Is it limited by bits or by characters? Does anyone has information about this?
EDIT: Yes, it's TPM 2.0 modules, embedded on Dell laptops and desktop... |
So pretty much all of the GNUTLS world is worrying about CVE-2014-3466. I checked my Kali and it responds with this -
# apt-cache rdepends libgnutls26 | grep -v lib
Reverse Depends:
telepathy-gabble
qemu-kvm
guile-gnutls
gnutls-bin
xxxterm
xpp
xfprint4
xfce4-mailwatch-plugin
xen-utils-4.1
x11vnc
... |
http://seclab.stanford.edu/websec/csrf/csrf.pdf points out that most CSRF protection mechanisms fail to protect login forms. As https://stackoverflow.com/a/15350123/14731 explains:
The vulnerability plays out like this:
The attacker creates a host account on the trusted domain
The attacker forges a login request in t... |
I think I have a basic understanding of security concerns, but I feel like if I don't know everything, I'm going to implement lousy solutions. Below is my current strategy; Have I overlooked obvious best practices?
I've read Can anyone provide references for implementing web application self password reset mechanisms p... |
The media are currently (and have been) creating a huge ruckus surrounding the supposedly "undetectable" Gameover Zeus malware.
The Daily Mail
The Mirror
The Independant
PC World
The Telegraph
...And a number of others.
My question is... is there actually any increased risk to this particular malware, or are the medi... |
To log in to a enterprise web app, our security team is insisting on 2FA as it is hosted on our internal network.
The proposed solution is to have a standard username (email address) and password login, which will then trigger a four digit PIN emailed to the user which they will have to enter to log in.
To my mind that... |
I want to understand the technical aspect of BitLocker and TPM, especially with Startup PIN. Does anyone know a technical survey report, preferred by a competent third party (not MS)?
I have a few questions about this topic
If I use the BitLocker StartUp PIN, do I use the TPM like a smart card?
Like a smart card, can ... |
If two persons use the same router, which has an embedded WiFi access point, for accessing the Internet, is it possible that one can see
HTTP traffic
HTTPS traffic
TOR traffic
of the other in the below mentioned scenarios?
Both connect to the router via its WiFi access point.
One connects to the router via its WiFi ... |
Suppose an attacker records all messages of a SSL handshake (RSA one-way), and starts a replay attack. When (after which message) can the server possibly detect the attack?
Now suppose the attacker changes strategy, and sends the first three phases (up to the session key exchange), but sends this sequence many times. W... |
I'm designing a system where some combination of hardware and software (lets call it an appliance...) sends asynchronous secure archival to the cloud. By secure, I mean, AES-256 encrypted, with AES key and IV encrypted by RSA-2048 public key. There may be several such appliances, each with the same RSA public key. It d... |
I'm working for a company that sells software products to customers some of which do not have the resources and/or know-how to build and maintain their own CA (used for the SSL communication of our software). In these cases we have to provide the certificates for them. The customers are completely independent and shoul... |
This is what facebook ships with their API php client: https://github.com/facebook/facebook-php-sdk-v4/blob/master/src/Facebook/fb_ca_chain_bundle.crt
It contains dozens (hundreds?) Root CAs.
But doesn't it make the client more prone to MitM attack?
To clarify why I think: it's more chance that some of CA certificates ... |
I have a reflected XSS vulnerability in my Web application.
I have decided to take the black-list approach instead of the popular white-list approach.
My question is can there exist a malicious javascript call without opening parenthesis(\u0028) and close paranthesis(\u0029)?
By malicious, I mean something that can imp... |
Does CVE-2014-0195 (openSSL) affect HTTPS or only VPN tunnels?
Reference: https://security-tracker.debian.org/tracker/DSA-2950-1, https://isc.sans.edu/
|
Given a proxy performing MITM SSL decryption and inspection, is it possible to install a wildcard certificate (*.domain.com) on the proxy signed by a root CA (such as VeriSign or GoDaddy) such that clients will not have to have a self-signed cert installed (since they will already trust the root CAs in their trusted st... |
I came across this link that dicusses how an attacker could exploit access control allow origin to get an anti-CSRF token:
http://yossi-yakubov.blogspot.com/2011/09/bypassing-token-protection-against-csrf.html
If the token in the above example was a one-use token (a new one is generated each time the page loads, and ex... |
In our web application, we allow customers to enter their bank account information as a method of payment (account number, routing number, bank name). This information goes nowhere at all; it's up to the client to process such payments using a separate system.
What, if anything, should we be doing to secure this data? ... |
I'm trying to get access into a Windows 2000 server through the vulnerability MS03_026. An exploit is provided by Metasploit but I don't know why it isn't working. After filling the options (basically the RHOST) and running it, it just says "Sending exploit" and return the prompt. Port 135 is wide open.
Playing with pa... |
Microsoft deployed a patch for Windows 2012 R2 and Windows 8.1 that adds the following ciphers.
Cipher suite Exchange Encryption Hash
TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 DH AES SHA384
TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 DH AES SHA256
TLS_RSA_WITH_AES_256_GCM_SHA384 ... |
This article describes how to disable old versions of TLS, but in addition to doing so, "Multi-Protocol Unified Hello" is also disabled.
# Disable Multi-Protocol Unified Hello
md 'HKLM:\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\Multi-Protocol Unified Hello\Server' -Force
New-ItemProperty -pa... |
Are there any tools or techniques that allow a scan of multiple sites for the use of tracking cookies, beacons, web bugs, or offsite javascript includes?
As far as I can tell, major web application scanners do not report on these attributes.
One can manually navigate to sites using Ghostery and Disconnect, but doing so... |
I'm trying to learn some attack methods by myself and I have hit a wall where I can't find any information. I have successfully performed an ARP MiTM between 2 systems and I am able to sniff the traffic using tcpdump, driftnet, etc.
My question is: How can I actively modify the packets by injecting HTML code into the r... |
Is the Double Submit Cookies mechanism vulnerable anything other than XSS and sub-domain attacks?
All CSRF protection mechanisms are vulnerable to XSS, so that's nothing new. I'm just wondering if I can safely rely on this mechanism so long as I ensure I control all sub-domains.
NOTE: This question is a spin-off of How... |
I have run a heartbleed detector from Lookout on my Android phone. It says:
The version of openSSL is affected by the heartbleed bug but the
vulnerable behaviour is not enabled.
What does it mean by not enabled?
I can see /system/lib/libssl.so file on the phone and found openssl on it. It shows 1.0.1c. Does that m... |
I have a server located in the USA and SSH to it from various places around the world. When I SSH in from a computer I have never used before, I'll see something like this:
The authenticity of host 'my.usa.server.com (11.22.33.44)' can't be established.
RSA key fingerprint is xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:b8:... |
Is it safe to copy a private key from one computer to another over SCP? Does this depend on whether you use the same key to authenticate the transfer?
|
I won't really go into details of how cookie tossing and cookie overflow attacks work, because this answer explains it perfectly. This post on github explains some mitigation strategies, but does not talk about the case where a.domain.com can do malicious things to b.domain.com.
The proposed solution is to host untrust... |
Given that user needs to store a copy of the same private key on each of his devices (in order to decrypt email and other data encrypted with the public key) ... what are some general techniques for sharing and optionally removing the private keys from a user's various devices?
Would a file sharing service suffice?
Do... |
I was wondering, a lot of software nowadays automatically connect to a server at launch to check for updates, even basic software, and, to my knowledge, this is a new trend. Before you had to download it all again from the website.
My guess is that some of them weren't designed with security in mind and simply check a... |
A website based on Apache Struts uses central authentication service (cas) for login. I'd like to know if additional csrf protection needs to be provided with Struts in case cas doesn't provide that.
Also, when credentials are submitted, cas generates a token in URL form. If I copy this URL and use it later, the user i... |
It is generally accepted that password change mechanisms should ask the user for their old password (e.g. OWASP) The reason being that an attacker who has temporary access to a user's session (be it through XSS, computer left logged-in, whatever) would only have access to that session.
Presumably this principle should ... |
I want to improve the security of my home wifi.
My neighbor wants to crack my Wi-Fi password with a nutcracker.
I tried to activate the protection by MAC address, but now my laptop and smartphone don't have access to the box. Is MAC address filtering effective?
How else can I secure my Wi-Fi?
|
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