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2

What the page you link to means is that there are known attacks which, when implemented, would allow building collisions with some costs: If the goal is "raw collisions" then the computational effort is equivalent to running 261 times the SHA-1 function. A raw collision is such that the attack produces two messages m and m' which are distinct but hash to ...


3

SHA1 hash has 160bits. If SHA1 was safe, you would need approximately 2^80 iterations to find a collision. Why 2^80 and not 2^160? Because of birthday paradox: http://en.wikipedia.org/wiki/Birthday_attack The general "collision finding" algorithm works like this: http://en.wikipedia.org/wiki/Cycle_detection#Tortoise_and_hare ...simply, to rabbits, one is ...


2

"Export" means ciphersuites that were designed to be sufficiently weak they could legally be exported from the US back in the 1990s when there were much stricter legal limits on exporting encryption from the US (and some other countries, but Netscape was in the US). See Which SSL/TLS ciphers can be considered secure? for a summary, various sections of TLSv1 ...


0

Is this the video you're referring to? If the site does not have HSTS (HTTP Strict Transport Security) enabled then I believe you can capture login information without generating a certificate warning using software like SSLstrip. SSLstrip does not bother forging a certificate; instead, it removes SSL entirely. Many webpages are accessible via both ...


0

Network speed bears no relation to this. As saint mentioned, it is likely the add-on. From an attack perspective, this would be possible by doing "SSL Stripping" during MiTM. SSL Stripping is the principle of the MiTM saying "switch all HTTPS links to HTTP." There's was an interesting defcon talk about this (click here to see it). In the presentation, the ...


1

In digital time, a full day apart does not seem like "almost the same time". As mentioned in the comments, this would also be done every two months, likely at a regular interval. IBM and Google aren't the only very big corporations, add in Amazon, Microsoft, Apple, etc. and chances are there will be some that land even closer than 1 day apart. Not to mention ...


1

"Websense" is a number versions of several different products, and without knowing which one is in use, I can't say for certain what the reason is that HTTPS connections are getting through. However, there are a couple of likely candidates: 1) Some Websense software does not have HTTPS proxy capabilities. Without this ability, the Websense software cannot ...


0

HTTPS is more secure and limits the ability of attackers to snoop or modify your connection. The filtering seems to be configured for both security concerns and content accessing.


0

Could be quite a bit of things but ... throttling is speed-related, not protocol related. You indicate yourself you installed something and it started, did you try turning it ( the add-on ) off and on again ? You should take note this might be part of a MITM ( man-in-the-middle ), someone eavesdropping. If dropping to HTTP also triggers request to renew or ...


2

So p is the modulus, and g is the generator. You are absolutely right. p and g are publicly known values, and the discrete log problem needs to be solved to break the Diffie-Hellman exchange. Ephemeral Diffie-Hellman The whole point of Ephemeral Diffie-Hellman is to provide for Perfect Forward Secrecy (PFS). Here's an answer I already wrote up on DHE ...


2

No matter which CA you go with, your users' assurance that they're actually communicating with your site and not an attacker is only as good as the worst CA their browser trusts - an attacker who wants to forge a certificate can shop for a CA with bad practices. So I don't see any plausible argument that your choice of CA impacts your site's security, unless ...


2

To answer the question directly, hash functions are used as part of the process of creating a digital signature. In fact, the signature itself is just a hash of the data being signed, encrypted with the signer's private key: Image from the Wikimedia Commons Therefore, the verification process involves decrypting the signature (using the signer's public ...


16

The browser already contains a copy of the root cert. Thus, it doesn't need to verify it through its signature. Even if you broke SHA-1, you couldn't replace the root certificate that is already stored in the browser.


6

For non-root CA certificates, the browser can only verify the certificate by validating the signature of the certificates hash. If the signed hash was generated by a weak algorithm, an attacker may be able to create a fake certificate with the same hash, but a different key pair. For a root certificate, however, this does not have to be a problem. Since the ...


0

Mainly There are 3 types of SSL Certificates: (1) Domain Validation SSL Certificates It has a less rigorous validation procedure. Only the applicant's name and contact information are checked and verified with the data that was entered during registration. The legitimate factor is not checked, and therefore, this is excellent for online sites or ...


18

A root certificate is a self-signed certificate (by definition). So how do you want to verify the signature of a root certificate? The root certificate is valid in itself, therefore you cannot verify it. This is also the most problematic part of root certificates: they cannot be validated independently. If they are in the browser, then they are trusted.


0

From Philipp C. Heckel's tech blog with some light edits: While attacking unencrypted HTTP traffic can be done without having to deal with X.509 certificates and certificate authorities (CA), SSL-encrypted HTTPS connections encrypt every request and response between client and server end-to-end. And because the transferred data is encrypted with a shared ...


1

Usually, digital signatures are not actually applied to the full data. Instead, the data (in the case the x.509 certificate) is hashed, and only the resulting hash is signed. If this were not the case, digital signatures would end up being at least as large as the message itself, and signing / verifying the files would be less efficient. This means, ...


16

Qualys' forums have your answer: https://community.qualys.com/blogs/securitylabs/2014/09/09/sha1-deprecation-what-you-need-to-know They started to flag SHA-1 7 days ago.


18

Nothing has changed in the industry. Qualys is now just highlighting what we already know. It is to give you a reminder that you should move away from SHA-1. It's not generally considered a critical problem yet, but should be sorted as part of normal refresh/update cycles.


15

It is because google is going to start marking certificates that use sha1 as insecure from 2017. Some more info Why google is hurrying the web to kill sha1


3

It is only a hash over the TLS messages themselves, and not the TCP data. TCP data is frequently modified in-route (think NAT, etc.) so attempting to hash that would be futile. Without knowing more about how it's failing, it's hard to say what the cause is. For example, if they're performing SSL MITM, then it would fail with client certificates, even if ...


0

That answer is most likely. It depends on the verification depth (or lack of) from the issuing certificate authority. With that being said, it sounds like you will still be breaking policy even if you find a CA that will issue a certificate based on email verification alone. Are you willing to suffer the repercussions if/when caught?


1

There is no need to involve a certificate authority (CA), or trusted 3rd party, when you control client and the server. By avoiding the need to have a CA, you are no longer threatened by rogue certificate authorities, and rogue certificate authority certificates. Using two self-signed certificates it is possible to create a very strong TLS connection ...


0

I haven't used android emulator but have used Fiddler to debug traffic on an iPad.


3

Yes and no. SSL offers end-to-end encryption between the application using SSL and the server to which you are connecting. It's a layer 6 protocol and may only provide security for that particular application. In case of IPSec, it works at layer 3. It's mostly used to provide end-to-end encryption between different sites. For instance, if you have several ...


3

The signature algorithm specified when creating the CSR corresponds to the message digest used to sign the request itself, it is not intented to ask the CA to prefer that algorithm when signing your certificate. The MD used in the CSR establishes the level of confidence in your request, but does not imply what algorithm is used on the certificate since ...


3

To answer your questions in order: 1) Mixed content. The typical StackExchange page combines content from a number of sources (ad servers, imgur, gravatar, etc.), and not all of these support HTTPS yet. Browsers react in varying ways to pages that contain a mix of HTTP and HTTPS content, but the most common is to refuse to load the insecure content, ...


0

paj28's solution works. I had to go to IcedTea's configuration and add the Burp certificate to the list of certificates and then configure IcedTEa to use Burp as a proxy. I don't now why but IcedTea seemed to mess up (refusing to launch the applet) at first, but after a few attempts it works!


0

It's common to terminate SSL (ie. decrypt traffic) at the first point where your network receives the traffic assuming your internal network can be considered secure. Often this is at a load balancer or caching proxy. In your scenario I'd terminate the SSL at nginx.


0

In addition to the reasons others have given already: Additional work required to set up HTTPS on the server The server administrator needs to purchase and renew certificates for each domain. The process of installing a certificate is time-consuming as for obvious security reasons you can't simply re-use the same certificate or just generate one yourself, ...


0

It is legal and possible for the CA to take a CSR and modify the DN it finds there before issuing the certificate. For instance, with StartSSL free certificates they ignore the DN provided and issue based solely on the public key, the domain name requested (CN), the country (C), and email of the requester (E). And according to the user interface, ...


6

When a CA signs a certificate they encrypt a hash which includes the host name of the certificate target using their private key. When the client receives the certificate they decrypt the hash using the public key for the CA (which is baked into the client) and check that it matches the hash calculated by the client. If the hashes don't match then validation ...


0

If they have your private key and you are not using PFS, they could inject malicious content in the traffic, steal anything that goes through in that HTTPS connection, redirect the people visiting the website, etc. It would be the best that you revoke your old CERT! If you still want to use your old cert then: When you configure the HTTPS server, use ONLY ...


1

Encryption with SSL consists of the following steps: Identify the peer using a certificate. Create and exchange keys for the following communication. Exchange data, encrypted with the previously exchanged keys. You are usually employing encryption because you think that anybody might listen to the connection. A small step from this passive listening is ...


2

If the attacker has the private key, they can fully impersonate you. They can perform MitM attacks on your traffic stream, they can redirect requests to your server in a manner undetectable to the client, and so on.


0

Its "only" the MITM problem, including the attacker not relaying the request to you at all. However, the attacker can't just decrypt your traffic, he can also modify it. For example, he could add a virus to the pdf, or add some pages/change some numbers. A csr isn't something that needs to be kept secret.


1

You're fine with a self-signed certificate. In my experience over several years, I never had any problems with a self-signed certificate on my mail server. I eventually switched to one signed by StartSSL and there was no discernible difference in interoperability. See also this post on ServerFault. The bottom line is, STARTTLS is about encryption, not ...


0

Added as an at-least-partial answer so I can format: Those files (in comment to @Steffen) do have an encoding difference. ServerGroupCertificate.cer has Subject containing Org and OrgUnit as PrintableString and CommonName as T61String aka TeletexString, and 12-Digit-Working.cer has Issuer the same, but 10-Digit-Broken.cer (which is also client_cert.pem) ...


2

BREACH and CRIME don't compromise sites, because they are attacks on clients, not on servers. The server is still involved in that, for instance, TLS compression won't be used unless the server agrees; so that, even if the CRIME attack targets the client, the server can refuse to use compression and this indirectly protects vulnerable clients. Both attacks ...


1

From the BREACH Wikipedia page: BREACH exploits the compression in the underlying HTTP protocol. Therefore, turning off TLS compression makes no difference to BREACH, which can still perform a chosen-plaintext attack against the HTTP payload. However CRIME can be mitigated by removing support for TLS compression. In TLS the compression algorithm is ...


2

How to avoid session fixation (Login CSRF) by MitM attack without HSTS? You can't. You need to have your site in the HSTS preloaded lists to avoid this type of MITM attack otherwise the attacker could MITM the first connection and set the session cookies to fixate it to the attacker's session. However, I cannot use HSTS because the same domain needs ...


1

The BREACH attack is a Side-Channel attack. You need some way to access the side channel. On page 13 of the presentation, you can see what BREACH needs the attacker to set up: A web server serving the site the browser visits. A callback where the javascript on the victim's browser notifies the attacker that the request completed, giving time information ...


32

In TLS, the client announces its maximum supported version. Then the server responds with the protocol version that will actually be used for the connection. So for instance, if a server knows TLS 1.0 and 1.1, and the client announces "I support up to TLS 1.2", the server, without knowing what TLS 1.2 may be, can still respond: "fine, we'll use 1.1". ...


0

Here is an architecture that could work: Generate an asymmetric encryption keypair. The private key will be known only to a program running on your mainframe that is the final endpoint that retrieves the data. On the web site, use a client-side JavaScript-based encryption library that can generate a symmetric encryption key of adequate strength, like AES ...


1

If you want a truly end to end solution for customers accessing their personal info (which resides on a mainframe in the bank's LAN) from a web service (hosted in their DMZ) you'll have to create a browser plugin for your customers. This will require them to spend an extra minute (as a first time user) to download & install your plugin ... but they ...


1

You do not want to generate a client certificate for your customer. This would mean that you have the private key for their communications. This is bad practice. You kind of have the right idea. You want to generate a Root CA Certificate for your main server. The customer would then generate an Intermediate CA Certificate for their server. They ...


2

Interesting question. What your are describing is an environment, where the attacker mounts a man-in-the-middle attack, where it can read and modify the users HTTP traffic but not HTTPS traffic. This excludes SSLStrip-like attacks and SSL man-the-middle so you might look here for ideas on how to detect these kind of attacks at the server. In the environment ...


1

HTTPS + certificate pinning seems like an obvious route.


6

As @anon said, the main issue is Information Leakage. Anyone who goes to any one of your sites can see the names of all the others listed in the certificate (unless you choose to get a wildcard certificate; however, a wildcard certificate won't let you add the extra level test.service..., because the wildcard cannot contain dots in it). If you don't care ...



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