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Ayush Ambastha
Ayush Ambastha
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The POODLE (Padding Oracle On Downgraded Legacy Encryption) attack affects any connection which uses SSL 3.0 as its encryption standard, along with CBC (Cipher Block Chaining). SSL 3.0 is an old standard and is replaced by TLS now, the problem stems from the fact that most SSL/TLS implementations remain backward compatible, to help with legacy systems. A malicious attacker can then force the secure connection to fail and fall back to SSL 3.0, which he can then attempt to attack.

SSL 3.0 uses either a block cipher in CBC, which mode or the RC4 stream cipher. The latter has an RC4 bias, because of which isif the same sensitive data is sent over multiple connections, information regarding the data is leaked. Though this will require the victim's browser to send hundreds of connections (It needs to make 256 SSL 3.0 requests to reveal one byte of encrypted messages, Wiki). Thus, to make these hundreds of connections, the attacker mounts a MITM attack.

So YES, They can sniff data even though you are using HTTPS!

An interesting point here is that Internet Explorer 6 does not offer support beyond SSL 3.0! So websites had to offer support for SSL 3.0 when IE 6 was initially released.

Ways to prevent this attack from happening?

  • Disable the use of SSL 3.0
  • Use TLS_FALLBACK_SCSV, You can read more about this here

The POODLE (Padding Oracle On Downgraded Legacy Encryption) attack affects any connection which uses SSL 3.0 as its encryption standard, along with CBC (Cipher Block Chaining). SSL 3.0 is an old standard and is replaced by TLS now, the problem stems from the fact that most SSL/TLS implementations remain backward compatible, to help with legacy systems. A malicious attacker can then force the secure connection to fail and fall back to SSL 3.0, which he can then attempt to attack.

SSL 3.0 uses CBC, which has an RC4 bias, because of which is the same sensitive data is sent over multiple connections, information regarding the data is leaked. Though this will require the victim's browser to send hundreds of connections (It needs to make 256 SSL 3.0 requests to reveal one byte of encrypted messages, Wiki). Thus, to make these hundreds of connections, the attacker mounts a MITM attack.

So YES, They can sniff data even though you are using HTTPS!

An interesting point here is that Internet Explorer 6 does not offer support beyond SSL 3.0! So websites had to offer support for SSL 3.0 when IE 6 was initially released.

Ways to prevent this attack from happening?

  • Disable the use of SSL 3.0
  • Use TLS_FALLBACK_SCSV, You can read more about this here

The POODLE (Padding Oracle On Downgraded Legacy Encryption) attack affects any connection which uses SSL 3.0 as its encryption standard, along with CBC (Cipher Block Chaining). SSL 3.0 is an old standard and is replaced by TLS now, the problem stems from the fact that most SSL/TLS implementations remain backward compatible, to help with legacy systems. A malicious attacker can then force the secure connection to fail and fall back to SSL 3.0, which he can then attempt to attack.

SSL 3.0 uses either a block cipher in CBC mode or the RC4 stream cipher. The latter has an RC4 bias because of which if the same sensitive data is sent over multiple connections, information regarding the data is leaked. Though this will require the victim's browser to send hundreds of connections (It needs to make 256 SSL 3.0 requests to reveal one byte of encrypted messages, Wiki). Thus, to make these hundreds of connections, the attacker mounts a MITM attack.

So YES, They can sniff data even though you are using HTTPS!

An interesting point here is that Internet Explorer 6 does not offer support beyond SSL 3.0! So websites had to offer support for SSL 3.0 when IE 6 was initially released.

Ways to prevent this attack from happening?

  • Disable the use of SSL 3.0
  • Use TLS_FALLBACK_SCSV, You can read more about this here
Source Link
Ayush Ambastha
Ayush Ambastha
  • 73
  • 6

The POODLE (Padding Oracle On Downgraded Legacy Encryption) attack affects any connection which uses SSL 3.0 as its encryption standard, along with CBC (Cipher Block Chaining). SSL 3.0 is an old standard and is replaced by TLS now, the problem stems from the fact that most SSL/TLS implementations remain backward compatible, to help with legacy systems. A malicious attacker can then force the secure connection to fail and fall back to SSL 3.0, which he can then attempt to attack.

SSL 3.0 uses CBC, which has an RC4 bias, because of which is the same sensitive data is sent over multiple connections, information regarding the data is leaked. Though this will require the victim's browser to send hundreds of connections (It needs to make 256 SSL 3.0 requests to reveal one byte of encrypted messages, Wiki). Thus, to make these hundreds of connections, the attacker mounts a MITM attack.

So YES, They can sniff data even though you are using HTTPS!

An interesting point here is that Internet Explorer 6 does not offer support beyond SSL 3.0! So websites had to offer support for SSL 3.0 when IE 6 was initially released.

Ways to prevent this attack from happening?

  • Disable the use of SSL 3.0
  • Use TLS_FALLBACK_SCSV, You can read more about this here