PS4 Remote Play Windows PC / Mac Use the (PS4 Remote Play) application to control your PlayStation®4 system from your computer. With this application installed on your PC or Mac, you'll enjoy immersive PlayStation® gaming while being connected remotely to your PS4™ system. Using the Controls Once you’re in replay mode you can control the camera angle, change the speed of the video, skip around the recording, and tweak the visuals. All the controls are right in front.

A replay attack (also known as playback attack) is a form of network attack in which a valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and re-transmits it, possibly as part of a masquerade attack by IPpacket substitution. This is one of the lower tier versions of a 'Man-in-the-middle attack'.

Another way of describing such an attack is:'an attack on a security protocol using replay of messages from a different context into the intended (or original and expected) context, thereby fooling the honest participant(s) into thinking they have successfully completed the protocol run.'^[1]

How a replay attack works[edit]

Suppose Alice wants to prove her identity to Bob. Bob requests her password as proof of identity, which Alice dutifully provides (possibly after some transformation like a hash function); meanwhile, Eve is eavesdropping on the conversation and keeps the password (or the hash). After the interchange is over, Eve (posing as Alice) connects to Bob; when asked for a proof of identity, Eve sends Alice's password (or hash) read from the last session which Bob accepts, thus granting Eve access.^[1]

Prevention and countermeasures[edit]

General countermeasure for all replay attacks[edit]

Replay attacks can be prevented by tagging each encrypted component with a session ID and a component number.^[1] Using this combination of solutions does not use anything that is interdependent on one another. Because there is no interdependency there are fewer vulnerabilities. This works because a unique, random session id is created for each run of the program thus a previous run becomes more difficult to replicate. In this case an attacker would be unable to perform the replay because on a new run the session ID would have changed.^[1]

More on session identifiers[edit]

Session IDs, also known as session tokens, are one mechanism that can be used to help avoid replay attacks. The way generating a session id works is as follows.

1. Bob sends a one-time token to Alice, which Alice uses to transform the password and send the result to Bob. For example, she would use the token to compute a hash function of the session token and append it to the password to be used.
2. On his side Bob performs the same computation with the session token.
3. If and only if both Alice’s and Bob’s values match, the login is successful.
4. Now suppose an attacker Eve has captured this value and tries to use it on another session. Bob would send a different session token, and when Eve replies with her captured value it will be different from Bob's computation so he will know it is not Alice.

Session tokens should be chosen by a random process (usually, pseudorandom processes are used). Otherwise Eve may be able to pose as Bob, presenting some predicted future token, and convince Alice to use that token in her transformation. Eve can then replay her reply at a later time (when the previously predicted token is actually presented by Bob), and Bob will accept the authentication.

One-time passwords[edit]

One-time passwords are similar to session tokens in that the password expires after it has been used or after a very short amount of time. They can be used to authenticate individual transactions in addition to sessions. These can also be used during the authentication process to help establish trust between the two parties that are communicating with each other.

Nonces and MAC[edit]

Bob can also send nonces but should then include a message authentication code (MAC), which Alice should check.

Timestamps[edit]

Timestamping is another way of preventing a replay attack. Synchronization should be achieved using a secure protocol. For example, Bob periodically broadcasts the time on his clock together with a MAC. When Alice wants to send Bob a message, she includes her best estimate of the time on his clock in her message, which is also authenticated. Bob only accepts messages for which the timestamp is within a reasonable tolerance. The advantages of this scheme is that Bob does not need to generate (pseudo-) random numbers, and that Alice doesn't need to ask Bob for a random number. In networks that are unidirectional or near unidirectional, it can be an advantage. The trade-off being that replay attacks, if they are performed quickly enough i.e. within that 'reasonable' limit, could succeed.

Countermeasures in specific scenarios[edit]

Kerberos protocol prevention[edit]

The Kerberos authentication protocol includes some countermeasures. In the classical case of a replay attack, a message is captured by an adversary and then replayed at a later date in order to produce an effect. For example, if a banking scheme were to be vulnerable to this attack, a message which results in the transfer of funds could be replayed over and over to transfer more funds than originally intended. However, the Kerberos protocol, as implemented in Microsoft Windows Active Directory, includes the use of a scheme involving time stamps to severely limit the effectiveness of replay attacks. Messages which are past the 'time to live (TTL)' are considered old and are discarded.^[2]

There have been improvements proposed, including the using a triple password scheme. These three passwords are used with the authentication server, ticket granting server, and TGS. These servers use the passwords to encrypt messages with secret keys between the different servers. The encryption that is provided by these three keys help aid in preventing replay attacks.^[3]

Secure routing in ad hoc networks[edit]

Wireless ad hoc networks are also susceptible to replay attacks. In this case the authentication system can be improved and made stronger by extending the AODV protocol. This method of improving the security of Ad Hoc networks increases the security of the network with a small amount of overhead.^[4] If there were to be extensive overhead then the network would run the risk of becoming slower and its performance would decrease. So by keeping a relatively low overhead the network can maintain better performance while still improving the security.

Challenge-Handshake Authentication Protocol[edit]

Authentication and sign-on by clients using Point-to-Point Protocol (PPP) are susceptible to replay attacks when using Password Authentication Protocol (PAP) to validate their identity, as the authenticating client sends its username and password 'in the clear', and the authenticating server then sends its acknowledgement in response to this; an intercepting client is therefore free to read transmitted data and impersonate each of the client and server to the other, as well as being able to then store client credentials for later impersonation to the server. Challenge-Handshake Authentication Protocol (CHAP) secures against this sort of replay attack during the authentication phase by instead using a 'challenge' message from the authenticator that the client responds with a hash-computed value based on a shared secret (e.g. the client's password), which the authenticator compares with its own calculation of the challenge and shared secret to authenticate the client. By relying on a shared secret that has not itself been transmitted, as well as other features such as authenticator-controlled repetition of challenges, and changing identifier and challenge values, CHAP provides limited protection against replay attacks.^[5]

Real world examples of replay attack susceptibility[edit]

There are several real world examples of how replay attacks have been used and how the issues were detected and fixed in order to prevent further attacks.

Remote keyless-entry system for vehicles[edit]

Many vehicles on the road use a remote keyless system, or key fob, for the convenience of the user. Modern systems are hardened against simple replay attacks, but are vulnerable to buffered replay attacks. This attack is performed by placing a device that can receive and transmit radio waves within range of the target vehicle. The transmitter will attempt to jam any RF vehicle unlock signal sent to it, while placing it in a buffer for later use. Upon further attempts to unlock the vehicle, the transmitter will jam the new signal, cache it, and play back the old one, creating a rolling buffer that is one step ahead of the vehicle. At a later time, the attacker may use this buffered code to unlock the vehicle.^[6][7]

Text-dependent speaker verification[edit]

Various devices use speaker recognition, to verify the identity of a speaker. In text-dependent systems, an attacker can record the target individual’s speech that was correctly verified by the system, then play the recording again to be verified by the system. A counter-measure was devised using spectral bitmaps from the stored speech of verified users. Replayed speech has a different pattern in this scenario and will then be rejected by the system.^[8]

See also[edit]

References[edit]

1. ^ ^abcdMalladi, Sreekanth. 'On Preventing Replay Attacks on Security Protocols'. oai.dtic.mil.
2. ^Olsen, Geir (1 February 2012). 'Kerberos Authentication 101: Understanding the Essentials of the Kerberos Security Protocol'. Redmond Magazine. Retrieved 2017-06-13.
3. ^Dua, Gagan (2013). 'Replay Attack Prevention in Kerberos Authentication Protocol Using Triple Password'. International Journal of Computer Networks & Communications. 5 (2): 59–70. arXiv:1304.3550. doi:10.5121/ijcnc.2013.5205.
4. ^Zhen, Jane (2003). 'Preventing Replay Attacks for Secure Routing in Ad Hoc Networks'. Ad-Hoc, Mobile, and Wireless Networks. Lecture Notes in Computer Science. 2865. pp. 140–150. doi:10.1007/978-3-540-39611-6_13. ISBN978-3-540-20260-8.
5. ^Simpson, William Allen. 'RFC 1994 - PPP Challenge Handshake Authentication Protocol (CHAP)'. tools.ietf.org. Retrieved 2018-09-12.
6. ^Beek, S. van de; Leferink, F. (1 August 2016). 'Vulnerability of Remote Keyless-Entry Systems Against Pulsed Electromagnetic Interference and Possible Improvements'. IEEE Transactions on Electromagnetic Compatibility. 58 (4): 1259–1265. doi:10.1109/TEMC.2016.2570303.
7. ^Francillon, Aurelien. 'Attacks on Passive Keyless Entry and Start Systems in Modern Cars'(PDF). eprint.iacr.org/. Retrieved 8 December 2016.
8. ^Wu, Z.; Gao, S.; Cling, E. S.; Li, H. (1 December 2014). Signal and Information Processing Association Annual Summit and Conference (APSIPA), 2014 Asia-Pacific. pp. 1–5. doi:10.1109/APSIPA.2014.7041636. ISBN978-6-1636-1823-8.

PlayerUnknown’s Battlegrounds continues to receive new features and updates since the game’s official release in December, and the latest addition is the introduction new replay controls. If you want to be able to easily surf through the footage, and find those epic clips easier, you’ll need to know how to use the replay controls. In this article we’ll break down everything to make it easier to understand how ot use replay controls in PUBG, that way you can get started sharing your clips with the world.

How to Use Replay Controls

The first thing to know before you dive into editing your replays is how to control the replay system in PUBG. The system was built from the ground up for PUBG, so players won’t have to worry about any issues from outside systems, as everything is built directly into the game. This makes it extremely easy to go through your replays and find the clips that you’re looking for.

Right now there isn’t any kind of replay system available for the Xbox One version of the game, so we’ll only be covering PC at the moment. However, we will update our article with the appropriate information once the replay system makes its way onto the Xbox One.

PC Controls

We’ve broken down the individual buttons that you’ll need to know below, so take a look and be sure to bookmark this page so you’ll always have the button configuration if you need it.

J – Turn the Timeline off and on.

P – Pause the replay.

Ctrl+U – Hide or show the HUD.

Up/Down Arrows – Change the speed of playback.

B – Focuses back on your character.

W, A, S, D – Allows you to move the camera up, down, left and right.

E, Q – Adjusts the height of the camera up and down.

Whiteboard online drawing. Holding Shift or Ctrl – Allows you to change your camera movement speed.

V or LMB – Lets you see the view of any selected playing, including FPP (first person perspective) if available.

C or RMB – Follows a selected player over the shoulder or in TPP (third person perspective)

F or Space – Allows you to freely move the camera around the map.

TAB – Opens the player list so that you can select the player you want to view.

L –Opens up the battle list, which lets you check engagements around you.

M – Opens the map up.

H – Shows all of the players in the match.

X – Opens up the X-ray mode, which allows you to see players through objects and things.

It may take some getting used to, but PUBG’s replay mode is one of the best out there, and if you take the time to learn it, you can create some really epic things, like clips, replays, and more. Be sure to head back over to our PUBG guide for even more helpful articles like this.

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About the author

Josh has been exploring fantastic worlds and getting lost in video games for as long as he can remember. Starting out on the Super Nintendo with Super Mario World, and ending up in the world of next-generation gaming. He enjoys digging into the story and lore of massive RPGs, as well as getting lost just trying to make that last jump in any platformers he gets pulled into, as well as everything in between. He holds a Bachelor of Fine Arts in Creative Writing for Entertainment.