Vulnerability Note VU#838200
Telerik Web UI contains cryptographic weakness
Original Release date: 25 Jul 2017 | Last revised: 25 Jul 2017

Overview
The Telerik Web UI, versions R2 2017 (2017.2.503) and prior, is vulnerable to a cryptographic weakness which an attacker can exploit to extract encryption keys.

Description
CWE-326: Inadequate Encryption Strength – CVE-2017-9248
The Telerik.Web.UI.dll is vulnerable to a cryptographic weakness which allows the attacker to extract the Telerik.Web.UI.DialogParametersEncryptionKey and/or the MachineKey.
Versions R2 2017 (2017.2.503) and prior are vulnerable.

Impact
A remote, unauthenticated attacker could perform arbitrary file upload and downloads, cross-site scripting attacks, leak the MachineKey, or compromise the ASP.NET ViewState.
Software vendors who use Telerik web components may also be impacted.

Solution
Apply an update
Please see the Telerik’s support article for update information for specific versions.

The support article also provides information to those who are unable to update their software.

Vendor Information (Learn More)

VendorStatusDate NotifiedDate UpdatedDotNetNukeAffected-18 Jul 2017
TelerikAffected-19 Jul 2017If you are a vendor and your product is affected, let
us know.

CVSS Metrics (Learn More)

Group
Score
Vector

Base
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P

Temporal
7.5
E:ND/RL:ND/RC:ND

Environmental
5.6
CDP:ND/TD:M/CR:ND/IR:ND/AR:ND

References

http://www.telerik.com/blogs/security-alert-for-telerik-ui-for-asp.net-ajax-and-progress-sitefinity
http://www.telerik.com/support/kb/aspnet-ajax/details/cryptographic-weakness
http://www.dnnsoftware.com/community-blog/cid/155436/critical-security-update–june-2017
http://www.dnnsoftware.com/community/security/security-center

Credit

Telerik thanks to Erlend Leiknes, security consultant in Mnemonic AS, and Thanh Van Tien Nguyen for reporting this vulnerability.
This document was written by Trent Novelly.

Other Information

CVE IDs:
CVE-2017-9248

Date Public:
26 Jun 2017

Date First Published:
25 Jul 2017

Date Last Updated:
25 Jul 2017

Document Revision:
11

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