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Apple Multiple Security Updates, (Mon, Oct 20th)

Mon, 10/20/2014 - 15:28


Apple released security update today for iOS 8 and Apple TV 7.

iOS 8.1 (APPLE-SA-2014-10-20-1 iOS 8.1) is now available for iPhone 4s and later, iPod touch (5th generation) and later, iPad 2 and later, to addresses the following:

Bluetooth CVE-2014-4448
House Arrest CVE-2014-4448
iCloud Data Access CVE-2014-4449
Keyboards CVE-2014-4450
Secure Transport CVE-2014-3566

Apple TV 7.0.1 (APPLE-SA-2014-10-20-2 Apple TV 7.0.1) is now available for Apple TV 3rd generation and later, to address the following:

Bluetooth CVE-2014-4428
Secure Transport CVE-2014-3566

[1] https://support.apple.com/kb/HT1222

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Guy Bruneau IPSS Inc. gbruneau at isc dot sans dot edu

Teaching SEC 503 end of October in Ottawa

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.
Categories: Vulnerability Pipes

TA14-290A: SSL 3.0 Protocol Vulnerability and POODLE Attack

Fri, 10/17/2014 - 11:27
Original release date: October 17, 2014 | Last revised: October 20, 2014
Systems Affected

All systems and applications utilizing the Secure Socket Layer (SSL) 3.0 with cipher-block chaining (CBC) mode ciphers may be vulnerable. However, the POODLE (Padding Oracle On Downgraded Legacy Encryption) attack demonstrates this vulnerability using web browsers and web servers, which is one of the most likely exploitation scenarios.

Overview

US-CERT is aware of a design vulnerability found in the way SSL 3.0 handles block cipher mode padding. The POODLE attack demonstrates how an attacker can exploit this vulnerability to decrypt and extract information from inside an encrypted transaction.

Description

The SSL 3.0 vulnerability stems from the way blocks of data are encrypted under a specific type of encryption algorithm within the SSL protocol. The POODLE attack takes advantage of the protocol version negotiation feature built into SSL/TLS to force the use of SSL 3.0 and then leverages this new vulnerability to decrypt select content within the SSL session. The decryption is done byte by byte and will generate a large number of connections between the client and server.

While SSL 3.0 is an old encryption standard and has generally been replaced by Transport Layer Security (TLS) (which is not vulnerable in this way), most SSL/TLS implementations remain backwards compatible with SSL 3.0 to interoperate with legacy systems in the interest of a smooth user experience. Even if a client and server both support a version of TLS the SSL/TLS protocol suite allows for protocol version negotiation (being referred to as the “downgrade dance” in other reporting). The POODLE attack leverages the fact that when a secure connection attempt fails, servers will fall back to older protocols such as SSL 3.0. An attacker who can trigger a connection failure can then force the use of SSL 3.0 and attempt the new attack. [1]

Two other conditions must be met to successfully execute the POODLE attack: 1) the attacker must be able to control portions of the client side of the SSL connection (varying the length of the input) and 2) the attacker must have visibility of the resulting ciphertext. The most common way to achieve these conditions would be to act as Man-in-the-Middle (MITM), requiring a whole separate form of attack to establish that level of access.

These conditions make successful exploitation somewhat difficult. Environments that are already at above-average risk for MITM attacks (such as public WiFi) remove some of those challenges.

Impact

The POODLE attack can be used against any system or application that supports SSL 3.0 with CBC mode ciphers. This affects most current browsers and websites, but also includes any software that either references a vulnerable SSL/TLS library (e.g. OpenSSL) or implements the SSL/TLS protocol suite itself. By exploiting this vulnerability in a likely web-based scenario, an attacker can gain access to sensitive data passed within the encrypted web session, such as passwords, cookies and other authentication tokens that can then be used to gain more complete access to a website (impersonating that user, accessing database content, etc.).

Solution

There is currently no fix for the vulnerability SSL 3.0 itself, as the issue is fundamental to the protocol; however, disabling SSL 3.0 support in system/application configurations is the most viable solution currently available.

Some of the same researchers that discovered the vulnerability also developed a fix for one of the prerequisite conditions; TLS_FALLBACK_SCSV is a protocol extension that prevents MITM attackers from being able to force a protocol downgrade. OpenSSL has added support for TLS_FALLBACK_SCSV to their latest versions and recommend the following upgrades: [2]

  • OpenSSL 1.0.1 users should upgrade to 1.0.1j.
  • OpenSSL 1.0.0 users should upgrade to 1.0.0o.
  • OpenSSL 0.9.8 users should upgrade to 0.9.8zc.

Both clients and servers need to support TLS_FALLBACK_SCSV to prevent downgrade attacks.

Other SSL 3.0 implementations are most likely also affected by POODLE. Contact your vendor for details. Additional vendor information may be available in the National Vulnerability Database (NVD) entry for CVE-2014-3566 [3] or in CERT Vulnerability Note VU#577193. [4]

References Revision History
  • October 17, 2014 Initial Release
  • October 20, 2014 Added CERT Vulnerability Note VU#577193 to the Solution section

This product is provided subject to this Notification and this Privacy & Use policy.


Categories: Vulnerability Pipes

Apple Updates (not just Yosemite), (Fri, Oct 17th)

Fri, 10/17/2014 - 07:42

Apple yesterday released the latest version of its operating system, OS X 10.10 Yosemite. As usual, the new version of the operating system does include a number of security related bug fixes, and Apple released these fixes for older versions of OS X today.

This update, Security Update 2014-005 is available for versions of OS X back to 10.8.5 (Mountain Lion).

Among the long list of fixes, here a couple of highlights:

Apple doesnt turn off SSLv3 in this release, but restricts it to non-CBC ciphers, limiting its exposure to attacks like POODLE and BEAST. The list of trusted certificate authorities has also been updates [2]

802.1x no longer supports LEAP by default due to weaknesses in this authentication method.

The bash fix, that was released as a standalone fix earlier to counter Shellshock, is included in this update.

An arbitrary code execution vulnerability in CUPS was fixed. (CVE-2014-3537)

And a quick note about OS 10.10 Yosemite:

After installing it, all security relevant settings Ichecked where untouched (good!). Among security relevant software, GPGMailwill not work with Yosemite yet, but according to the developers, a fix is in the work and may be release in a few weeks, but GPGMail may no longer be free. If you rely on software that you compiled with MacPorts: Wait for the release of XCode 6.1, as it is required to recompile the software for OS X 10.10. In general, it is adviced that you FIRST update all your software and then upgrade to Yosemite. Little Snitch, another popular piece of security software for OS X, works well with Yosemite, but I recommend you turn off the network filter during the upgrade (it works with it enabled, but you need to approve a lot of new connections from new software).

[1]http://support.apple.com/kb/HT1222
[2]http://support.apple.com/kb/HT6005

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Johannes B. Ullrich, Ph.D.
STI|Twitter|LinkedIn

(c) SANS Internet Storm Center. https://isc.sans.edu Creative Commons Attribution-Noncommercial 3.0 United States License.
Categories: Vulnerability Pipes