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2

Keep in mind the context here - since it's an interview question, the goal is to assess your understanding of the terminology and concepts. They were probably not interested in some specific tool, or an exact command you would be running (although you might get kudos for knowing something like that). As mentioned in comments, there are MANY specifics ...


3

If you notice that someone is actively man-in-the-middling a server the first thing you should do is inform your incident response/security team. They should decide on mitigating controls, that's their task. It's highly dependable on what technology is being MiTM and in what way. It also depends largely on where the MiTM is occuring. Aside from ...


0

In the first messages between client and server, both send their list of supported algorithms, in order of preference. Then the algorithm that will be used is the first one on the client list that also appears somewhere in the server list. This is specified in RFC 4253, section 7.1: encryption_algorithms A name-list of acceptable symmetric encryption ...


1

There are a few ways that you can detect if you are a victim of a MITM attack, where the attacker has the ability divert traffic and/or to create bogus certificates from a trusted CA. In the case where you are connecting to a host that you've previously connected to, certificate pinning can be used. With certificate pinning, your client stores the ...


3

Your point 2 is a bit inaccurate. The PTK is never sent over the air in WPA; it is computed from the PMK, an AP nonce, a client nonce, the AP MAC address, and the client MAC address (this is "key exchange", but the PTK never gets transmitted). Without the PMK, an attacker who sniffs the data can't discover the PTK without doing a brute-force attack ...


2

There is already an infrastructure to manage trust and it's called "Public Key Infrastructure". This is the basis of all the SSL/TLS protocols used over the internet and websites. The main idea is to designate a Trusted Third Party (TTP) which is recognised by all the parties involved. These TTP issues their public key and they are shipped by default in ...


2

Not really, no. First, some terms. You mention ARP spoofing; this is not something you can detect at the IP level. ARP is what tells you which MAC address to address your frames to in order to send them to a given IP; ARP spoofing means you think you're sending them to the right IP, but your device addresses them to the attacker at the MAC layer. This can, ...


0

I would suggest you to try scapy, if you're doing it on linux. It has great features for the case you need. https://samsclass.info/124/proj11/proj16x-promscan.html


1

The seminal work on detection of promiscuous interfaces on the network is Detection of Promiscuous Modes using ARP Packets: ...promiscuous mode detection is performed by checking the responses of ARP packets, when ARP request packets are sent to all nodes on the network I don't know of implementations offhand, but the paper is detailed enough for ...


1

If the thieves man-in-the-middle connections to saas.example.com and present the wildcard cert, would the customer getting man-in-the-middled get any sort of SSL-related warning from their browser? Usually not because the attacker presents a non-revoked certificate which is valid for the accessed host. The client would only reject the valid certificate ...


15

CA does not issue private keys to anybody. CA signs (using its own private key, which is kept very secret) your public key. The CA has no access to your private key at all. If the CA’s private key is leaked to Mallory, Mallory is able to issue valid certificates for any name. That means he can make almost undetectable (well, obviously, you can detect the ...


3

It sounds like what you have there is a VPN option known as "split tunnelling" set-up. In this configuration, traffic for your home network is directed over the VPN and all other traffic goes straight to its destination. If your goal is to protect all your general traffic from sniffing attacks in the coffee shop or other location that you access it from, ...


2

The way LUKS works is that it stores a (mostly encrypted) header on the underlying storage device. This header contains, among some other metadata, the actual data encryption key, encrypted under one or more passphrase-derived keys. This is what the LUKS "key slots" are for. dm-crypt works essentially the same way, minus the header. For the purposes of your ...


1

This all depends on which traffic your interested in. If you want to decrypt the traffic between your client and the device, then it is possible with a proxy. In fact, it is very similar to how Superfish works. See Lenovo Is Breaking HTTPS Security on its Recent Laptops for an outline of how superfish works. On the other hand, if you want to decrypt the ...


1

Assuming they're not evil, their MITM firewall will generally have the same set of trusted root certificates as your OS so any real MITM attacks or invalid certificates will be rejected by their MITM firewall. It's not possible to "add" their certificate at the end. They will directly generate a new certificate for the destination website signed with their ...


3

Take a Look at the FREAK tls vulnerability. you should be able to inject data into the SSL negotiation to trick the device into a RSA Export cipher, and from there the decryption of traffic by a man in the middle is significantly easier ( aka possible. ) Charles is written in java, shouldn't be too hard to modify to exploit this automatically.


42

The entire point of SSL is its resistance to eavesdropping by man-in-the-middle attacks like the one you're proposing. If you cannot make the client device trust your self-signed certificate, then your only options are: Intercept an initial HTTP request and never let the communication be upgraded to HTTPS (this will not work if the site has an HSTS record ...


11

Any suggestions? Is is doable? You need to own a certificate trusted by the device to intercept the traffic. How this can be achieved depends on how proper and open the certificate validation on the device is. The device might have a buggy or non-existing validation of certificates. This is typically No validation at all, in which case you could use ...


3

No. This is the point of SSL, to prevent this kind of unauthorized snooping. To authorize your proxy you need to tell the device to trust the proxy certificate, and tell the device clients to trust your certificate or use the devices private key, which it sounds like you don't have access to. For more information: ...


3

No, the very nature of HTTPS is that the certificate is required to decrypt it. You could sniff the traffic, but it would be encrypted and useless to you.


0

Removing old cruft such as support for export ciphers is often seen as a cost saving measure so the code doesn't have to be maintained. Old code like this is often like a submarine. Hard to detect unless it makes itself known, or unless someone is specifically looking for it. It becomes like an appendix. Relatively useless, and can easily be lived ...


3

There are many servers which support export-grade ciphers simply because default cipher sets had, and in some cases (inexplicably) continue to have them enabled. One of the changes in TLS 1.1 (section A.5) was to state that export grade ciphers MUST NOT be used in TLSv1.1. TLS 1.0 (section D.4) leaves it up to the implementation to decide on the required ...


5

These keys are still active because like so many other things the web is fundamentally broken for the purposes of backwards compatability. Technology vendors are quite often stuck with the choice between doing the right thing and supporting what is out there already. Could you imagine the uproar against Google and Apple if they shipped a web browser that ...


7

While your question, why are there so many servers offering export ciphersuites, is valid, your description of the problem is in error. FREAK is: a class of client-side bugs exploitable due to server-side configuration. The vulnerable devices you list are not configured to use export-grade ciphersuites, but they can be tricked into using export-grade key ...


1

I would have to say that if you have a privacy concern then you should not be using devices which you see as compromised or risky, the onus is on you to do this. Would you do a bank transfer by giving your details to your worst enemy and asking them to do it ? I have had employers which have essentially blocked Internet access off to prevent this The ...


2

I think the basic idea here is "unauthorized access." If the school accessed a student's non-school account, there can be a case made for the school accessing that account without authorization. There are a couple things that could negate matters: The account is a school account - the school is authorized because it is their account The network access ...


0

My two cents: If ur friend is on a *nix system, he can first note the MAC address of the router from the router web panel, and then run the following command: arp -a He can verfiy the MAC address that the router is at in the ARP table. If the MAC address of the router is different than what it should be, that is one indication. Secondly, You can verify ...


2

In the most simple and insecure case, both the file and the checksum are served via a plaintext protocol like HTTP or FTP. In this case, no, there is nothing to prevent Man-in-the-Middle modification of both the file and the checksum. Your first question, though, was, "Why do some processes rely on published checksums?" The answer is that, if properly ...


0

No. Checksums are only there to verify your download, in order to prevent transfer errors. Of course, a man in the middle could present a fake directory, with infected binary files and correct recreated checksums lists. The way to prevent this is to sign your checksums with PGP or S/Mime. Else you could checksum your checksum list and send the result via ...


4

Your problem is a common problem in security know as authentication. Checksum solves the problem of integrity, you know that what you just downloaded is correct, but you do not know from who it comes. If someone is operating a MitM attack, they obviously will try to replace the checksum of whatever download you required with the checksum of the binary they ...


0

Files can get downloaded and passed around. At some point, they can be modified maliciously. By posting the checksum on a site, it provides a 2nd vector of verification. In order for a bad actor to be successful, they will also have to be able to hack the vendor's website and modify the hash (checksum).


2

When you are under an MITM attack, typically the attacker has complete control of part of the link between you and your intended destination. For this reason, it is usually difficult to "bypass" MITM, if done correctly, because the attacker is fully in control of your traffic and free to direct it to wherever he pleases. The attacker can basically just ...


0

while the other amswers are correct about implementation details, the security issue in play is one of authorization. In the case of Superfish and related stuffs, the system owner typically doesn't want Superfish to be able to read all the stuff that is sent and received via HTTPS. On your home computer, you probably don't want Superfish to have your ...


-1

From your post I understand that you are talking about ARP poisoning MITM attack. After ARP poisoning done , attacker simply changes the responses of your DNS request with his desired input. If you can detect the malicious ARP responses then you can simply switch to static ARP, (if you know the gateway of your network) then you can cut the attack.


39

What makes Superfish, and similar products (all herein just referred to as "Superfish"), different from corporate MitM is that Superfish is doing the MitM on the client machine. Corporate MitM is performed on a separate server or appliance. This is important because the system performing the MitM must have the private key of a Trusted Root CA in order to ...


4

The main difference between Superfish and a Corporate Proxy is how the new SSL certificate is generated. In the Superfish case, the CA certificate and the private key stands on the client computer, and the software generates a new SSL certificate with a key it have on itself. The traffic is intercepted locally, a new certificate is generated on the client, ...



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