Pass-the-Hash Attacks

What Is a Pass-the-Hash Attack? 

A pass-the-hash (PtH) attack is a cyberattack where threat actors steal encrypted—or hashed—user credentials. Stored hashed passwords are leveraged to create new authenticated sessions on the target network, granting threat actors access to a system. PtH enables threat actors to move laterally within compromised networks, extracting sensitive information and credentials to carry out additional malicious activities.  

How Pass-the-Hash Attacks Work

Hashing employs an encryption algorithm to convert user passwords into fixed-length strings of characters. This makes it difficult to reverse-engineer the original passwords and ensures they are not stored in plain text. Threat actors use operating systems that support hashing, such as Windows.

Pass-the-Hash Attack Steps

1. Infiltration

Social engineering techniques are typically employed to breach networks. Once inside a system, various techniques are leveraged to infiltrate credential storage and access hashed passwords.

2. Extraction

Rather than decrypting hashed passwords, threat actors extract them from the system’s memory or database, bypassing the need for actual passwords during authentication and gaining them access to the system.

3. Advancement

Once unauthorized entry has been secured, threat actors gain complete control over systems, enabling lateral movement. They expand their reach across networks by escalating domain privileges and infiltrating more systems.

Examples of Pass-the-Hash Attacks

In February 2021, Centrais Elétricas Brasileiras (Eletrobras) and Companhia Paranaense de Energia (Copel), two significant Brazilian electric utility firms, were targets of ransomware attacks facilitated by PtH methodology. Threat actors extracted hashed passwords from the active directory database and moved laterally to obtain sufficient permissions to execute the ransomware assault.
In April 2022, the Hive ransomware-as-a-service (RaaS) platform deployed a coordinated PtH attack against numerous Microsoft Exchange Server clients across multiple industries. The assault used a Microsoft Exchange Server vulnerability identified as ProxyShell, which threat actors leveraged to plant a backdoor web script on the Exchange server and execute malicious activities. 

How to Prevent Pass-the-Hash Attacks

Effective security strategies to prevent PtH attacks include the following:
ZTNA enforces strict authentication and authorization controls, requiring additional verification factors beyond passwords. This cybersecurity solution significantly reduces the risk of stolen hashed credentials being exploited for unauthorized access.
MDR is a proactive solution against cyber threats, continuously monitoring all networks and endpoints. It leverages threat detection and rapid incident response, mitigating system breaches and preventing potential impacts of cyberattacks.

Password Management

Enforcing frequent password changes and unique administrative credentials minimizes PtH attacks, as it prevents threat actors from leveraging password vulnerabilities. 
PoLP limits user access to only the essential resources and privileges needed to perform tasks, reducing the potential impact of compromised systems. If a system is breached, PoLP ensures threat actors have limited capabilities, preventing them from moving laterally or accessing more sensitive data.

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