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How To Hack Emails

Mike Blinkman
8 min readMar 13, 2024

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Photo by Stephen Phillips - Hostreviews.co.uk on Unsplash

Common Tactics for Exploiting Email Systems

Some common vulnerabilities in email systems that hackers exploit to gain access include phishing attacks, email spoofing, man-in-the-middle attacks, impersonation, directory harvesting, and open relay abuse (GetGDS).

Phishing attacks and credential stuffing are common tactics used by hackers to target email systems. Phishing attacks involve sending deceptive emails or messages to trick victims into clicking on malicious links or entering their email credentials on fake login pages, giving attackers access to the email account. Credential stuffing, on the other hand, involves cybercriminals using automated tools to try username and password combinations from previous data breaches, potentially gaining access to email accounts (BeyondEncryption).

Email spoofing is used in attacks to deceive people into believing that the message comes from a known or trusted source, in order to trick them into engaging with the email as if it is legitimate. This can lead to various malicious activities such as phishing, spreading malware, or tarnishing the sender’s reputation (Norton). By using forged sender addresses, cybercriminals target businesses and individuals, aiming to trick recipients into opening the email and interacting with its content, which can include malicious links or attachments (CrowdStrike). Email spoofing takes advantage of the limitations in SMTP (Simple Mail Transfer Protocol) which does not verify if the email address in the From field is genuine, allowing attackers to manipulate the sender information and make the email appear legitimate (Heimdal Security).

Email System Vulnerabilities

There are specific types of phishing attacks that are particularly prevalent in targeting email systems, such as mass-market emails and spear phishing. Mass-market emails are the most common form of phishing, where attackers send general emails pretending to be someone else to trick recipients into taking actions like logging into a fake website or downloading malware (CSO Online). On the other hand, spear phishing involves targeting specific individuals or organizations with personalized and sophisticated attacks to deceive them into revealing sensitive information or taking harmful actions (ProPrivacy). These types of phishing attacks are commonly used to target email systems due to their effectiveness in tricking users and gaining unauthorized access to sensitive data.

Email spoofing is performed by cybercriminals who manipulate the email header fields such as FROM, REPLY-TO, and RETURN-PATH to make the email appear as if it is coming from a known or trusted source, when in fact it is not. They do this by exploiting the lack of built-in security in the Simple Mail Transfer Protocol (SMTP), which does not have an authentication mechanism. This technique aims to deceive recipients into believing the spoofed email is legitimate and from a trustworthy sender, leading them to engage with the email, click on links, download attachments, or provide sensitive information, making them vulnerable to phishing attacks or malware distribution (Norton, CrowdStrike, Fortinet).

Phishing emails play a significant role in compromising email systems by tricking users into providing sensitive information or downloading malware through social engineering tactics, leading to identity theft, spreading malware, reputation damage, and business email compromise (Forbes, BeyondEncryption, CSO Online).

Hackers can use malicious email attachments to compromise systems by sending emails containing files that appear harmless but actually contain malware. When users open these attachments, the malware is executed, leading to various threats such as system compromise, data breach, and theft. Hackers can gain unauthorized access to systems and networks, establish persistent threats, steal confidential information, and spread malware across networks by exploiting these attachments as gateways for their attacks (Proofpoint).

Exploiting Users

Hackers exploit email users through emails or phone calls, where they pretend to be trusted figures like managers or vendors, creating a sense of urgency or fear to manipulate recipients into clicking on malicious links or downloading malware-infected attachments. These tactics aim to deceive employees into disclosing sensitive information or granting unauthorized access to company devices, making phishing attacks a common method used by hackers to target organizations and individuals (MitnickSecurity).

Phishing itself is highly effective, with 65% of US organizations experiencing a successful phishing attack in 2019 (CSO Online). Scammers use various tactics such as deploying shortened URLs, utilizing real brand logos, and sending a huge number of emails to increase their chances of success (ProPrivacy). The effectiveness of phishing attacks lies in their ability to deceive users and exploit human vulnerabilities in recognizing suspicious messages (Google Blog).

The risks associated with malicious attachments and links in emails include compromising or damaging the recipient’s computer system, exfiltrating sensitive information, unleashing malware such as ransomware, spyware, or viruses, leading to system corruption, spreading to other devices, and potentially causing widespread compromise and disruption across networks (Proofpoint). Cybercriminals often use phishing emails to deceive users into opening malicious attachments, aiming to gain unauthorized access to personal information or sensitive data (GuardianDigital). By being cautious, verifying the sender’s identity, and recognizing signs of potentially unsafe attachments, individuals can avoid falling victim to these phishing attempts and maintain control over their digital environment (GuardianDigital).

Account Takeovers

Email account takeover is the unauthorized access or control of someone else’s email account by cybercriminals, who gain access through various malicious methods to obtain sensitive information, financial details, or to use the compromised account as a launchpad for further attacks (BeyondEncryption, KeeperSecurity). Anyone with an email account is at risk of email account takeover (BeyondEncryption). This type of attack can result in the cybercriminal locking the legitimate user out of their account, monitoring their activities, accessing sensitive data, taking control of other accounts, and even impersonating the user (KeeperSecurity). In the case of cloud email account takeovers, attackers targeted Office 365 and G Suite accounts, with a success rate of breaching 15 out of every 10,000 active user accounts, often originating from Nigeria or China (Comparitech).

Hackers achieve email account takeover through various methods such as those previously mentioned. Additionally, hackers may gain access to email accounts by stealing login credentials or finding them on the dark web, enabling them to lock users out of their accounts, monitor activity, access sensitive information, take over other accounts, and impersonate the user (KeeperSecurity).

Hackers typically gain access to email accounts through techniques mentioned above Additionally, hackers exploit security vulnerabilities like weak passwords through target-specific attacks, like guessing login credentials to gain unauthorized access to email accounts (KeeperSecurity). Such attacks can also target other devices such as Hacking a target’s IoT devices or by targeting Multi-Factor Authentication (MFA) systems. Hackers may also impersonate trusted individuals to carry out further attacks, especially targeting high-profile figures like politicians, activists, or CEOs, as attacks from their accounts are more likely to evade detection by email security (Egress).

Reconnaissance Techniques & Evading Detection

Hackers utilize email reconnaissance techniques to gather information for targeted attacks by collecting victim identity information such as email addresses, which can reveal opportunities for reconnaissance, establish operational resources, and gain initial access. This information can be gathered through various methods such as using public APIs, open-source research, website contact forms, and targeting specific individuals through spearphishing campaigns. By gaining access to email accounts through phishing attacks or credential stuffing, hackers can monitor conversations, track interesting information, and eventually launch targeted attacks using insider information and believable contexts to deceive the targets effectively (MITRE ATT&CK, BeyondEncryption, CSO Online).

Hackers evade detection and mitigation measures when targeting email systems by using various techniques such:

  • customizing payloads to avoid signature-based detection,
  • modifying source code to lower detection rates,
  • renaming files to bypass detection systems,
  • disabling monitoring by manipulating registry entries with PowerShell commands.

These techniques allow hackers to remain undetected for extended periods or for specific operational windows, ultimately increasing the success of their attacks. (eSecurity Planet)

Additionally, attackers can utilize evasion techniques to remain undetected for extended periods or exploit a specific window of opportunity for their attacks (eSecurity Planet). As defensive technologies evolve, security companies are increasingly focusing on behavioral analysis, active endpoint protection, and leveraging AI and ML techniques to detect zero-day threats due to the continuous advancement of evasion tactics used by hackers (eSecurity Planet).

The vulnerabilities inherent in email systems present exploitable opportunities for hackers through various tactics such as phishing, email spoofing, and credential stuffing. These tactics, exacerbated by the absence of robust security measures within protocols like SMTP, produce considerable risks for both individual users and organizations alike.

  • Phishing emerges as a prominent threat due to its adeptness in deceiving users and subsequently compromising email accounts, thereby precipitating identity theft, malware dissemination, and business email compromise.
  • Email account takeovers constitute a significant menace, granting adversaries unauthorized access to sensitive information, the ability to monitor activities, and the potential to impersonate legitimate users.

Mitigation strategies necessitate user vigilance, authentication verification, and the adoption of stringent security protocols. Given the perpetually evolving tactics and evasion techniques employed by attackers, it is imperative to implement both cybersecurity awareness training for all employees, and up-to-date detection and mitigation measures to safeguard email systems from exploitation.

References

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Hacking
Cybersecurity
Email
Vulnerability
Information Security

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Mike Blinkman
Mike Blinkman

Written by Mike Blinkman

76 Followers
8 Following

Cybersecurity blogger dissecting vulnerabilities and exploits in well-known and well-used systems to demonstrate both hacking and mitigation strategies.

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