TLS Padding Oracle Vulnerability in Citrix NetScaler ADC and NetScaler Gateway

Published: 2017-12-13 15:30:55
Severity Low
Patch available YES
Number of vulnerabilities 1
CVE ID CVE-2017-17382
CVSSv3 5.7 [CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N/E:F/RL:O/RC:C]
CWE ID CWE-310
Exploitation vector Local network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software Citrix NetScaler
Vulnerable software versions Citrix NetScaler 12.0 Build 53.13
Citrix NetScaler 12.0 Build 41.24
Citrix NetScaler 12.0 Build 53.6
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Vendor URL Citrix

Security Advisory

1) TLS Padding Oracle

Description

The vulnerability allows a remote attacker to decrypt TLS traffic. A TLS padding Oracle issue has been detected in Citrix NetScaler Application Delivery Controller (ADC) and NetScaler Gateway. A remote attacker with ability to establish a large number of TLS connections with the target server can conduct a modified version of the Bleichenbacher chosen-ciphertext attack against RSA PKCS#1 v1.5 encryption block formatting and decrypt the data. The attack is known as "ROBOT" (Return Of Bleichenbacher's Oracle Threat).

Remediation

Install updates from vendor's website:

  • Citrix NetScaler ADC and NetScaler Gateway version 12.0 earlier than build 53.22
  • Citrix NetScaler ADC and NetScaler Gateway version 11.1 earlier than build 56.19
  • Citrix NetScaler ADC and NetScaler Gateway version 11.0 earlier than build 71.22
  • Citrix NetScaler ADC and NetScaler Gateway version 10.5 earlier than build 67.13

External links

http://support.citrix.com/article/CTX230238
https://eprint.iacr.org/2017/1189

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