Heartbleed Vulnerability: OpenSSL Technical Analysis and Mitigation

This report provides an in-depth analysis of the Heartbleed vulnerability, a critical security flaw affecting the OpenSSL cryptographic software library. It begins with an executive summary highlighting the vulnerability's impact, which allowed attackers to steal sensitive information from a significant percentage of HTTPS sites. The technical description details the vulnerability, emphasizing its exploitation through the TLS heartbeat extension, where attackers could manipulate requests to read system memory. The report outlines attack vectors, explaining how malicious actors crafted requests to extract confidential data, including user credentials and encryption keys. Mitigation strategies include upgrading to secure OpenSSL versions, using detector tools, and restarting services. The exploitation scenario illustrates how attackers could send malicious heartbeat requests to extract sensitive data. Remediation measures include strong passwords, key regeneration, and certificate revocation. The report concludes by emphasizing the severe implications of the vulnerability on information security and privacy.

Executive Summary
The Heartbleed vulnerability was first detected in April 2014 and took the Internet by storm. The
vulnerability allowed the malevolent entities to read sensitive information from approximately 24-
55% of popular HTTPS sites [1]. The vulnerability is associated with OpenSSL (Open source
projects). The research paper includes the description of the Heartbleed vulnerability along with the
parameters and the steps that are involved. Mitigation and remediation steps are also covered in the
paper.
Technical Description
Exploitation Description
The Heartbleed Bug is one of the most severe vulnerabilities that are observed in the OpenSSL
cryptographic software library. It provides the ability to the malevolent entities to steal the protected
information that is secured by the application of SSL/TLS encryption [6]. The implementation
version 1.01 of OpenSSL and 1.02 beta versions, there are critical programming errors that may
expose the confidential data sets. The systems that utilize these versions of OpenSSL can also face
security compromise as an outcome. The primary loophole has been detected in the Request/Respond
TLS module under OpenSSL. These heartbeat requests can be manipulated by any entity using the
Internet which may provide the ability to read through the system’s memory utilizing the vulnerable
versions of OpenSSL. As a result, the secret keys that are used to protect the information sets, such
as user credentials, traffic encryption, service provider identity, etc. gets compromised. The
malicious entities get the opportunity to eavesdrop on the networks and acquire the information sets
through the services or user. Impersonation attacks are given shape as a result [2].
Attack Vectors
Attackers benefit from the vulnerabilities that emerge due to heartbeat request message and they
develop requests in such a manner that the server responds with the confidential and sensitive data
sets. Impersonation of services or users is utilized to give shape to the attack. The following are the
parameters that are involved in the Heartbeat Request Message.
 Payload: There is certain information that is included in it
 Size: The size of the payload is mentioned to information the server regarding the same
 The actual attack occurs in the following steps:
 Attacker validates and verifies that the target machine is on and is successfully running

 Attacker develops a request message that has certain payload along with the fake size of the
payload

 The server or the target machine receives the request message that is transmitted by the
attacker
 While the response message is created, the payload size is checked by the machine. For
instance, in this case, it is 30, whereas the actual size is actually 4 bytes.
 The payload size is completed in the response message and the data sets from the heap
memory are acquired and transmitted. For instance, additional 26 bytes are transmitted in this
case.
Every server that utilizes OpenSSL makes use of its specific heap memory for data storage. The
majority of the data sets in this case include the sensitive and secure information that is stored at the
time of a session [3]. For example, user credentials, secure keys for encryption and decryption,
financial details of the user, etc. are stored. The same data is exposed during transmission as
illustrated in the example above. If the malicious entities get hold of the historical data sets, then the
security keys may also be acquired which may be used to decrypt the information and data sets. This
may have severe implications on the information security and privacy.
Mitigation
It is necessary that the vulnerable versions are upgraded to the secure OpenSSL 1.0.1g. There may be
confusions regarding the vulnerability of the application in terms of Heartbleed attacks. However,
there are detector tools that have been developed to detect this vulnerability. If the application if
found as non-vulnerable then there will be no action required. However, if vulnerability is detected,
upgrades and security patches shall be installed. All the services that make use of OpenSSL shall be
restarted. Before any of the SSL or TLS application is access, a vulnerability check must be
performed as a mandatory step [4]. Logging in to the impacted sites shall be avoided. The business
partners and third-parties shall also be informed about the same.

Exploitation Scenario
a) In order for SSL to work, the client’s browser needs to send packets (hearbeats) to the remote
server so as to ensure that the client is still alive and able to receive messages.
b) Occasionally either the client or the server may send a heartbeat request i.e., an encrypted
piece of message to one another and the other will reply back with the same encrypted piece.
c) The vulnerability here is that the receiving server or client never checked to ensure whether
the request being received is exactly as long as it’s stated to be.
d) The attacker here would send multiple malicious request to the server and the server responds
back to whatever message the requester has send along with some other fragments stored in
the memory. Once the attacker learns a lot of sensitive data about the server, the attacker
would misuse this information to launch a full-fledged attack or perhaps retrieve other
people’s sensitive information [5].
Remediation
There are certain measures that may be adopted by the end-user
 Use of strong passwords and frequent change of passwords
 Re-generation of private keys
 Revocation of the certificates

References
[1]The Heartbleed Story. 2016.
[2]Heartbleed OpenSSL Vulnerability. 2017.
[3]S. Gujrathi, "Heartbleed Bug: AnOpenSSL Heartbeat Vulnerability", Network Security, vol.
2014, no. 5, pp. 1-2, 2014.
[4]The Heartbleed Bug: How To Protect Your Business with Symantec. 2018.
[5]A. Borges, How to perform a HeartBleed Attack. 2014.