a.
Cipher attack models refer to different scenarios or levels of knowledge that an attacker may
have regarding the encryption process or the ciphertext. These models help in understanding
the potential vulnerabilities of a cryptographic system. Describe the Four(4) Cipher attack
models.
b. In a large multinational corporation, strict security measures are in place to protect sensitive
data
and electronic files containing confidential information. Given the Corporation's policies below,
identify the following concepts: Security Violation; Vulnerability, Attacker, Attack Vector;
and Threat
i. Only authorized employees, referred to as "Approved Users", are allowed to access and
handle sensitive data or electronic files.
ii. Only Users are authorized to Extract or Download electronic files from the company's secure
servers.
c. Omni Bank is a leading financial institution that recently experienced a severe data breach
incident. The breach compromised sensitive customer information, including personal and
financial data. As a result, the bank suffered significant reputational damage and financial
losses.
Analyze Omni's Bank data breach incident in the context of the six (6) high-level computer
security goals, then Identify and discuss how each of the goals could have been addressed to
prevent or mitigate the impact of the breach.
SOLUTION
a. Four Cipher Attack Models
The four primary cipher attack models represent different levels of knowledge and access an
attacker has:
1. Ciphertext-Only Attack (COA) This is the most basic attack model where the attacker only
has access to the ciphertext. The attacker must deduce the plaintext or encryption key using
only the encrypted data. This requires exploiting patterns, statistical analysis, or weaknesses in
the cipher algorithm itself.
2. Known-Plaintext Attack (KPA) Here, the attacker has access to both some plaintext and its
corresponding ciphertext. This additional information can help identify patterns in the encryption
process or deduce the encryption key. Historical examples include breaking the Enigma
machine during WWII using known message formats.
3. Chosen-Plaintext Attack (CPA) The attacker can choose specific plaintext messages and
obtain their corresponding ciphertext. This allows for systematic testing of the encryption
algorithm by selecting strategic inputs to reveal information about the key or algorithm structure.
4. Chosen-Ciphertext Attack (CCA) The most powerful attack model where the attacker can
choose specific ciphertext and obtain the corresponding plaintext (except for the target
ciphertext). This might occur when an attacker has temporary access to a decryption device or
service.
b. Security Concepts Analysis
Based on the corporation's policies, here are the identified security concepts:
Security Violation: Any instance where unauthorized personnel access sensitive data or
electronic files, or when approved users extract/download files without proper authorization.
Vulnerability: The potential for unauthorized access exists if authentication systems fail,
access controls are bypassed, or if there are gaps in monitoring who accesses what data.
Attacker: Could be internal (disgruntled employees, negligent authorized users) or external
(hackers attempting to gain unauthorized access to sensitive systems).
Attack Vector: Potential pathways include compromised user credentials, privilege escalation
by authorized users, social engineering to gain access, network infiltration, or exploitation of
system vulnerabilities in the secure servers.
Threat: The potential for data theft, industrial espionage, financial fraud, regulatory violations,
or reputational damage resulting from unauthorized access to sensitive information.
c. Omni Bank Data Breach Analysis
The six high-level computer security goals and how they could have prevented/mitigated the
breach:
1. Confidentiality This goal ensures information is only accessible to authorized individuals.
Omni Bank could have implemented stronger encryption for data at rest and in transit, robust
access controls with multi-factor authentication, and data classification systems to identify and
protect the most sensitive information.
2. Integrity This ensures data remains accurate and unaltered. The bank could have deployed
digital signatures, checksums, and hash functions to detect unauthorized modifications. Regular
data validation processes and secure backup systems would help maintain data integrity.
3. Availability This ensures systems and data remain accessible to authorized users when
needed. Implementing redundant systems, disaster recovery plans, and distributed
architectures would prevent complete system failures and minimize downtime during security
incidents.
4. Authentication This verifies the identity of users and systems. Stronger authentication
mechanisms such as biometric verification, hardware tokens, and continuous authentication
monitoring could have prevented unauthorized access even with compromised credentials.
5. Authorization This ensures users can only access resources they're permitted to use.
Implementing principle of least privilege, role-based access controls, and regular access
reviews would limit the scope of any breach by restricting what compromised accounts can
access.
6. Non-repudiation This provides proof of actions taken by users or systems. Comprehensive
audit logging, digital signatures for transactions, and tamper-evident log systems would help
trace the breach, identify responsible parties, and provide evidence for legal proceedings while
also serving as a deterrent.
By comprehensively addressing these six goals through layered security measures, Omni Bank
could have significantly reduced the likelihood of the breach occurring and minimized its impact
if it did occur.
