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Wednesday, 9 April 2014

Should I be concerned about Heartbleed?

If you are running HTTPS, SFTP, or any other SSL enabled service on the Internet, you *NEED* to know about this!

There!  Now that that is out of the way... What is Heartbleed?   

Heartbleed in a nutshell, is a bug in the OpenSSL that could allow a malicious attacker to:
  • Steal OpenSSL private keys
  • Steal OpenSSL secondary keys
  • Retrieve up to 64kb of memory from the affected server
  • As a result, decrypt all traffic between the server and client(s)
OpenSSL has already committed a fix for this issue here on Github

This flaw/vulnerability will mostly affect UNIX/Linux/BSD and associated services such as Apache Webserver.

Information on common clients:
  • Windows (all versions): Probably unaffected (uses SChannel/SSPI), but attention should be paid to the TLS implementations in individual applications. For example, Cygwin users should update their OpenSSL packages.
  • OSX and iOS (all versions): Probably unaffected. SANS implies it may be vulnerable by saying "OS X Mavericks has NO PATCH available", but others note that OSX 10.9 ships with OpenSSL 0.9.8y, which is not affected. Apple says: "OpenSSL libraries in OS X are deprecated, and OpenSSL has never been provided as part of iOS"
  • Chrome (all platforms except Android): Probably unaffected (uses NSS)
  • Chrome on Android: 4.1.1 may be affected (uses OpenSSL). Source. 4.1.2 should be unaffected, as it is compiled with heartbeats disabled. Source.
  • Mozilla products (e.g. Firefox, Thunderbird, SeaMonkey, Fennec): Probably unaffected, all use NSS 
  •  Any service that supports STARTLS (imap,smtp,http,pop) may also be affected.
 Note:  Exploit code is publicly available for this vulnerability.  Additional details may be found in CERT/CC Vulnerability Note VU#720951.

If you are running internal servers protected by OpenSSL, you can validate their vulnerability status by using this python tool:   ->  Python tool to test internal SSL server

For a full explanation of the Heartbleed flaw in OpenSSL Go read these!

Affected Vendor Information (from CERT)

VendorStatusDate NotifiedDate Updated
Debian GNU/LinuxAffected07 Apr 201408 Apr 2014
Fedora ProjectAffected07 Apr 201408 Apr 2014
Fortinet, Inc.Affected07 Apr 201409 Apr 2014
FreeBSD ProjectAffected07 Apr 201409 Apr 2014
Gentoo LinuxAffected07 Apr 201408 Apr 2014
GoogleAffected07 Apr 201409 Apr 2014
Juniper Networks, Inc.Affected07 Apr 201409 Apr 2014
Mandriva S. A.Affected07 Apr 201407 Apr 2014
NetBSDAffected07 Apr 201408 Apr 2014
OpenBSDAffected07 Apr 201408 Apr 2014
openSUSE projectAffected-09 Apr 2014
Red Hat, Inc.Affected07 Apr 201408 Apr 2014
Slackware Linux Inc.Affected07 Apr 201407 Apr 2014
UbuntuAffected07 Apr 201407 Apr 2014
InfobloxNot Affected07 Apr 201408 Apr 2014

 According to OpenSSL:
OpenSSL Security Advisory [07 Apr 2014]

TLS heartbeat read overrun (CVE-2014-0160)

A missing bounds check in the handling of the TLS heartbeat extension can be
used to reveal up to 64k of memory to a connected client or server.

Only 1.0.1 and 1.0.2-beta releases of OpenSSL are affected including
1.0.1f and 1.0.2-beta1.

Thanks for Neel Mehta of Google Security for discovering this bug and to
Adam Langley  and Bodo Moeller  for
preparing the fix.

Affected users should upgrade to OpenSSL 1.0.1g. Users unable to immediately
upgrade can alternatively recompile OpenSSL with -DOPENSSL_NO_HEARTBEATS.

1.0.2 will be fixed in 1.0.2-beta2.
 And According to US Cert: National Cyber Awareness System:

TA14-098A: OpenSSL 'Heartbleed' vulnerability (CVE-2014-0160)
04/08/2014 08:46 AM EDT

Original release date: April 08, 2014
Systems Affected
  • OpenSSL 1.0.1 through 1.0.1f
  • OpenSSL 1.0.2-beta
A vulnerability in OpenSSL could allow a remote attacker to expose sensitive data, possibly including user authentication credentials and secret keys, through incorrect memory handling in the TLS heartbeat extension.
OpenSSL versions 1.0.1 through 1.0.1f contain a flaw in its implementation of the TLS/DTLS heartbeat functionality. This flaw allows an attacker to retrieve private memory of an application that uses the vulnerable OpenSSL library in chunks of 64k at a time. Note that an attacker can repeatedly leverage the vulnerability to retrieve as many 64k chunks of memory as are necessary to retrieve the intended secrets. The sensitive information that may be retrieved using this vulnerability include:
  • Primary key material (secret keys)
  • Secondary key material (user names and passwords used by vulnerable services)
  • Protected content (sensitive data used by vulnerable services)
  • Collateral (memory addresses and content that can be leveraged to bypass exploit mitigations)
Exploit code is publicly available for this vulnerability.  Additional details may be found in CERT/CC Vulnerability Note VU#720951.


This flaw allows a remote attacker to retrieve private memory of an application that uses the vulnerable OpenSSL library in chunks of 64k at a time.

OpenSSL 1.0.1g has been released to address this vulnerability.  Any keys generated with a vulnerable version of OpenSSL should be considered compromised and regenerated and deployed after the patch has been applied.

US-CERT recommends system administrators consider implementing Perfect Forward Secrecy to mitigate the damage that may be caused by future private key disclosures.

Heartbleed Check Site: Validate status of Internet facing servers 
Python tool to test internal SSL server 
TA14-098A: OpenSSL 'Heartbleed' vulnerability (CVE-2014-0160)
CERT: Vulnerability Note VU#720951 

OpenSSL fix on Github