#VU9651 TLS Padding Oracle in Citrix NetScaler - CVE-2017-17382

Vulnerability identifier: #VU9651

Vulnerability risk: Low

CVSSv4.0: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:A/U:Clear

CVE-ID: CVE-2017-17382

CWE-ID: CWE-310

Exploitation vector: Adjecent network

Exploit availability: Public exploit is available

Vulnerable software:
Citrix NetScaler

Software vendor:
Citrix

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).

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

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