What is Prepending in Cyber Security? Types, Risks & Defense

What is Prepending in Cyber Security? Types, Risks & Defense

In a world where technology intertwines seamlessly with daily operations, understanding the modus operandi of cyber threats has become paramount. Prepending is a type of cyber attack that is on the rise and catching many by surprise. Often used to bypass cybersecurity filters and controls, prepending attacks prey on human error and have become an insidious threat to individuals and organizations alike.

In this blog post, we will define what is prepending in cyber security, what is prepending attack, provide real-world examples of prepending attacks, and contrast it with other similar forms of cyber threats like typosquatting and pretexting.

By understanding key differences like prepending vs. typosquatting and prepending vs. pretexting, individuals and organizations can better protect themselves against this insidious cyber threat.

Table of Contents

Definition of Prepending in Cyber Security


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Prepending in cybersecurity involves a sophisticated technique wherein hackers clandestinely insert malicious characters or code at the onset of a legitimate file, string, or command.

This manipulative act serves as a digital camouflage, enabling the attacker to disguise their malevolent intent beneath a veneer of authenticity.

To understand what is prepending in cyber security, consider this scenario:

An email attachment that appears totally above board and from a trusted source drops into the inbox of an unassuming user. However, beneath the guise, a nasty surprise lies in wait.

As soon as the user opens up the boobytrapped attachment, the malicious code that was lurking dormant within the prepended content springs into action.

This code that was tacked on through prepending could potentially wreak havoc, exposing sensitive information, leaking data, or even blasting open a pathway for cybercriminals to infiltrate the entire system.

Once this Trojan horse attachment infiltrates its way into a device or network, attackers can often covertly comb through confidential files, siphon off critical data, and gain a foothold to advance their criminal schemes.

Examples of Prepending Attacks  

  • One common prepending attack example is tacking malware onto legitimate files or documents. Cybercriminals may prepend a malicious script or program to something like a PDF or Word doc. When the file is opened, the harmful code hidden through prepending activates, potentially exposing the system.
  • Another prepending technique is sticking malicious links onto the front of valid URLs or email links. The prepended content allows the link to bypass security filters and tricks users into clicking through to hazardous sites.
  • Prepending can also be used to dupe users through DNS (Domain Name System). Attackers register malicious domains by adding extra characters to the beginning of legitimate business sites. This redirects traffic from the real site to prepended impersonator domains where data can be intercepted.
  • Pretexting leverages made-up scenarios and false contexts to manipulate users into handing over sensitive info. Prepending builds on this by crafting convincing-looking domains and URLs to reel in victims. The combo makes for an extremely sly attack.

Prepending vs. Other Cyber Security Techniques

Let’s now delve into the specifics of how prepending compares to alternative cybersecurity techniques. Learn which approach is most effective for your unique security needs.

Prepending vs. Typosquatting: Differences and Similarities

Although prepending and typosquatting share the stage as crafty cyber deception tactics, they play different roles in pulling the wool over users’ eyes.

Prepending sneaks its way into the spotlight by sneakily tacking malicious content onto the front end of legitimate files or domains. This technique preys on people’s tendency to trust familiar-looking entities right off the bat.

Typosquatting, on the other hand, works behind the scenes by quietly registering domains with slight typos that users may inadvertently fat-finger their way into.

Both ploys bank on human error to work their magic, whether it’s falling for an authentic-looking file or slipping up with a wrong keystroke.

However, prepending relies more on technological trickery to mislead, while typosquatting spins its web through subtle linguistic and spelling snares.

Essentially, prepending puts on a show of appearing above the board through technical deception. Typosquatting works more in the shadows to craft traps and lure targets in based on innocent mistakes.

Here’s a table outlining the differences and similarities between Prepending vs. Typosquatting in cybersecurity.





Inserts malicious content at the start of legitimate data

Registers domain names similar to legitimate ones


Manipulates files, strings, or commands

Exploits user’s typographical errors in website addresses


Conceals malicious intent through content manipulation

Deceives users with similar-looking domain names

User Interaction

Direct interaction with manipulated content

Indirect interaction through mistyped domain names

Vulnerability Exploited

Trust in recognizable formats

Human errors in typing website addresses

Detection Difficulty

Harder to detect due to camouflaged start

Detection relies on careful scrutiny of domain names


Evades detection by hiding within legitimate content

Redirects users to malicious sites through confusion


Malicious payload may compromise data or systems

Users may unknowingly engage with fraudulent sites

Method of Attack

Manipulation of files, strings, or commands

Creation of deceptive domain names


Regular security audits to identify anomalous content

Domain monitoring and education to avoid typographical errors


Security measures to detect and remove prepended content

Domain monitoring and legal action against impostor domains

At the end of the day, prepending and typosquatting each leverage different techniques to dupe unsuspecting cyber citizens.

Prepending vs. Pretexting: Differences and Similarities

While prepending and pretexting are both cyber ruses, they play different roles in pulling a fast one on internet users.

Pretexting involves spinning an elaborate story to manipulate victims into handing over sensitive data. Attackers will conjure up fake scenarios, contexts, and rationales for why a target should lower their defenses and supply information.

Things like pretending to need credentials for an “urgent IT system fix” or impersonating positions of authority are common pretexting ruses. This technique relies on smooth-talking and wholly fabricated narratives to trick people.

Prepending, on the other hand, grabs the spotlight by sneakily tacking on malicious code to the start of files or websites to make them appear legit. This technical trick preys on people’s tendency to let their guard down with familiar-looking entities.

Yet despite their contrasting approaches, both capitalize on human vulnerability – whether it’s falling for a convincing story or trusting a familiar-looking domain.

Prepending relies on stealthy technical stunts to trick its audience. Pretexting spins an intricate web of lies to play on people’s emotions. Each technique contributes its own rhythm to the concert of cyber deception.

Here’s a table outlining the differences and similarities between Prepending vs Pretexting in cybersecurity:





Inserts malicious content at the start of legitimate data

Deceptive narrative to trick victims into sharing information

Attack Strategy

Manipulates files, strings, or commands

Crafts false pretext to exploit human psychology

Deception Technique

Camouflages malicious intent within legitimate content

Utilizes persuasive narratives to create false scenarios


Focuses on manipulating technical entities

Targets human psychology to extract sensitive information

Victim Interaction

Direct engagement with manipulated content

Victim voluntarily shares information due to false pretext

Vulnerability Exploited

Trust in recognizable formats

Human emotions, trust, and willingness to help

Detection Difficulty

Requires careful scrutiny of content and behavior

Detection hinges on recognizing deceptive narratives


Evades detection by embedding malicious content

Exploits human behavior for information extraction


Security measures to detect and remove prepended content

Employee training and awareness to recognize deceptive narratives

Defense Focus

Technical defenses and monitoring

Human-centric defenses and skepticism against false pretexts


Malicious payload compromises data or systems

Victim unknowingly divulges sensitive information

At the end of the day, prepending and pretexting take different routes to reach the same destination – compromising unsuspecting targets.

Impact of Prepending Attacks

Let’s now unpack the severity and long-term effects of prepending assaults on both individual devices and network systems.

Risks and consequences of prepending attacks

Here are the risks and consequences of Prepending attacks:

Credential Theft

Attackers can harvest usernames, passwords, and API keys to infiltrate accounts and systems. Stolen credentials caused 19% of damaging data breaches in 2022, with an average breach cost of $4.50 million.

According to the 2022 Ponemon Institute State of Cybersecurity report, over half (54%) of all security incidents involved credential theft, spotlighting it as a top attack vector.

Data Exfiltration

Confidential info like customer records, financial documents, and IP can be stolen and sold.

In the US, data exfiltration accounts for a majority (62%) of insider threat incidents, making it the most common type of insider attack.

Malware/Ransomware Attacks

Prepending provides an avenue to inject malicious code that can destroy systems. Staggering statistics show there are about 1.7 million ransomware attacks globally per day, equaling 19 attacks every second.

In just the first half of 2022, nearly 237 million ransomware attacks occurred worldwide. At the current trajectory, ransomware is expected to cost victims around $265 billion annually by 2031.

Operational Disruption

Prepending enables DDoS attacks and system infiltrations that bog down operations. Microsoft reported mitigating an average of 1,955 DDoS attacks daily in 2022, a 40% annual increase that shows the scale of this threat.

In one high-profile incident, Cloudflare stopped a massive DDoS attack reaching 17.2 million requests per second, underscoring how Prepending-enabled DDoS can severely disrupt organizations.

Reputational Damage

Incidents stemming from Prepending can hurt consumer and public trust. In 2022, companies paid an average of $1.5 million due to reputation damages stemming from cyber incidents.

Additionally, 25% of small business owners victimized by cyberattacks report losing business, according to 2022 statistics. It can take organizations up to 8 months to bounce back reputation-wise from a publicly known attack enabled by threats like prepending.

Financial Loss

There are costs associated with system recovery, legal fines, and breach notifications. Businesses may face revenue loss due to downtime and a tarnished reputation, leading to a decline in customer trust.

The cumulative financial impact can be staggering, and it often extends well beyond the immediate aftermath of the attack.

Compliance Violations

Loss of regulated data can lead to non-compliance penalties. Such violations can result in additional fines and legal repercussions, adding another layer of complexity and cost to the incident.

Moreover, failure to comply with regulations can lead to heightened scrutiny from governing bodies, potentially affecting future business operations.

Identity Theft

Compromised personal data obtained via prepending can enable identity fraud. This not only endangers the individuals whose information has been stolen but also creates a ripple effect that can lead to unauthorized transactions, credit issues, and long-term damage to one’s financial standing.

Addressing the consequences can be a complicated, time-consuming process, further highlighting the severity of these attacks.

Increased Vulnerability

Footholds gained by attackers provide launch pads for additional crimes. These initial points of entry can be exploited for further attacks, such as ransomware or data breaches, amplifying the potential damage.

The lingering vulnerabilities can also make the compromised system a target for other malicious actors, thereby escalating the level of risk over time.

Potential damage to systems and data

Prepending attacks can unleash severe harm on systems and data if organizations don’t batten down cyber defenses. Successful prepending schemes give attackers an opening to infiltrate networks and run rampant.

Sensitive data like customer records, financial documents, and intellectual property can be quietly siphoned off and sold by cyber criminals who breach systems. Confidential personal information stolen through prepending can also enable identity fraud if the data gets leaked.

Prepending techniques can provide pathways for injecting destructive malware and ransomware that holds files hostage or totally wipes out systems. The costs to restore compromised networks can quickly snowball for victims.

Vital business operations may be kneecapped by denial-of-service attacks powered through Prepending vectors. Regulated organizations can face hefty penalties if compromised systems lead to non-compliance with data protection laws.

Prevention and Mitigation of Prepending Attacks

Let’s now discuss some proven strategies for preventing and mitigating the impact of prepending attacks, helping you navigate the complex landscape of digital security.

Equip yourself with the knowledge and tools necessary to fortify your systems and networks against this evolving cyber threat.

Educating users about the risks of prepending

  • Conduct awareness training on Prepending red flags like slight URL/domain modifications
  • Inform users of new Prepending varieties observed targeting the organization
  • Advise against clicking suspicious links or downloading unsolicited files
  • Caution users not to enter data on sites with typos or minor misspellings

Strengthening security measures to prevent prepending incidents  

  • Employ advanced spam filtering to catch phishing emails
  • Enable strong endpoint protection to block malware insertion
  • Regularly patch networks, apps, and systems to eliminate exploits
  • Require strong passwords and multi-factor authentication

Implementing strong network security protocols  

  • Adopt DNS security extensions like DNSSEC to prevent spoofing
  • Monitor traffic for odd BGP route detours indicating hijacking
  • Disable unused ports and protocols to reduce the attack surface

Conducting regular security audits and assessments  

  • Do phishing drills to gauge staff readiness against lures
  • Red team your systems and networks to find gaps
  • Review logs regularly for signs of compromise

Keeping software and systems up to date  

  • Always apply the latest security patches promptly
  • Phase out end-of-life operating systems and apps
  • Automate updates for third-party software

Tools and strategies for detecting and mitigating prepending attacks

  • Use threat intelligence to stay on top of new Prepending varieties
  • Draw up and test incident response plans for swift containment
  • Enable logging with analytics to detect atypical traffic patterns

Case Studies of Prepending Attacks

Let’s now examine real-world instances of prepending attacks to shed light on their tactics, impact, and countermeasures that proved effective.

Gain invaluable insights through these case studies, arming yourself with practical knowledge to better defend against similar threats in the future.

BGP Rerouting Incident

According to a detailed 300+ page report unveiled to the US Congress, China Telecom stirred up a suspicious routing ruckus earlier this year that rerouted a huge chunk of the world’s internet traffic through Chinese servers.

On April 8, 2010, for around 18 minutes, China Telecom blasted out faulty network traffic routes, which instructed US and international data flows to detour through servers located in China.

Routers around the globe quickly latched onto these paths, funneling traffic to about 15% of the internet’s sites through Chinese-based machines. This internet hijacking kicked data bound for the US government and military domains like .gov and .mil into the twists and turns of China’s cyber turf.

Crucial agencies like the Senate, Department of Defense, NASA, and more got caught up in the rerouting of snafu. Even some commercial sites like Dell, Yahoo, Microsoft, and IBM took unexpected trips through Chinese servers.

The underlying culprit was a well-worn routing issue called IP hijacking. Routers use the Border Gateway Protocol (BGP) to map out the best path between two IP addresses.

When questionable routing info gets advertised, routers everywhere can get bamboozled into sending data on wacky geographical detours. In this case, China Telecom spread incorrect BGP routing intel that duped global routers into taking a Chinese side journey.

While the traffic detour may have been accidental, the incident highlights the fragile trust underlying internet infrastructure.

BGP Hijack on Amazon’s Route 53 DNS Service

In April 2018, threat actors pulled off a cunning BGP hijack to pilfer cryptocurrency from unsuspecting users. The attack focused on Amazon’s Route 53 DNS service and leveraged it to siphon money from the popular crypto wallet site MyEtherWallet.


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The scheme started when eNet/XLHost, an ISP based in Ohio, fell victim to a breach. Hackers infiltrated their network and reconfigured the routers to hijack Amazon’s Route 53 IP address space for around two hours.

While the bogus routes didn’t spread globally, major public DNS providers like Google DNS picked them up – amplifying the impact.


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When users queried MyEtherWallet.com, the imposter DNS redirected them to a fake clone site hosted on a server in eastern Ukraine. This fraudulent site was rigged and ready to steal login credentials and drain currency from the wallets of anyone who took the bait.

Fortunately, Amazon detected the hijack quickly and restored their DNS service after a couple of hours before major cascading damage could unfold. However, some MyEtherWallet users still fell prey, with reports indicating over $150,000 worth of Ethereum swiped through the scheme.

The incident spotlights the success hackers can have by tinkering with BGP and DNS to misdirect traffic and set traps. It pays to be wary of any sudden changes in domain resolution. Users should double-check sites before entering any sensitive information, especially in the wild west world of cryptocurrency.

2018 BGP Hijack Attacks

In July 2018,  three major US payment processors were caught in the crosshairs of concerning BGP hijack attacks. The routing assaults aimed to secretly divert traffic destined for the companies’ DNS servers into the hands of cybercrime groups to harvest data.

According to Oracle’s report, the first signs of trouble arose on July 6th, 2018, when a short attack tried to reroute networks belonging to payment firms Vantiv and Datawire.

More network blocks were targeted in hijacks throughout the month, including repeats against Vantiv and Datawire lasting up to 3 hours. Mercury Payment Systems also fell victim to a BGP misdirection gambit.

In two brazen incidents on July 10th and 13th, 2018, Oracle observed data rerouted from Datawire’s networks taking detours out of eastern Ukraine before getting funneled to suspicious servers in Curaçao.


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By tampering with BGP in 2018, the attackers schemed to quietly intercept payment processor traffic bound for DNS servers and siphon it to machines under their control. The sensitive customer and transaction data could then be filtered out and exploited.

While the duration of the hijacks varied, the report peeled back the curtain on the cybercrime group’s growing ambition and success in leveraging BGP’s fragile trust to misdirect key financial infrastructure in 2018.


While prepending schemes may seem like a minor manipulation on the surface, their potential to wreak havoc is immense. A single successful prepending attack can provide the foothold malicious actors need to breach entire networks, exfiltrate sensitive data, unleash ransomware, and spark chaotic fallout.

By shining a light on what is prepending in cyber security and real-world examples, individuals and organizations can inoculate themselves against this insidious threat.

Staying vigilant for telltale signs like slightly altered domains and errant traffic routes allows potential victims to spot and squash attacks before the damage spins out of control.

While cybercriminals will continue dreaming up new varieties of prepending ploys, knowledge, and preparation are the best defenses for protecting assets against old and emerging tricks alike.

Bolster your cybersecurity skillset and open up new career opportunities with CCS Learning Academy’s CISSP certification training. This comprehensive course arms you with up-to-date knowledge covering the latest Prepending threats and more.

Gain hands-on practice identifying and mitigating emerging attack techniques like prepended malware, phishing lures, and BGP hijacking. Boost your resume and step up to new cybersecurity roles with an industry-recognized CISSP certification.


1. What is prepending in cybersecurity?

Prepending in cybersecurity refers to the technique where malicious characters or code are added at the beginning of a legitimate file, string, or command. This allows attackers to disguise their intentions and infiltrate systems more easily.

2. How is a prepending attack carried out?

A prepending attack often starts with an email attachment or a link that appears legitimate. Once the user interacts with it, the malicious code hidden through prepending activates and potentially compromises the system.

3. What types of attacks can utilize prepending?

Prepending can be used in various types of attacks, including phishing, malware distribution, and DNS spoofing, among others. It serves as a means to bypass security measures by appearing legitimate.

4. What’s the difference between prepending and typosquatting?

While both are deceptive tactics, prepending involves adding malicious code to legitimate files or links, whereas typosquatting involves registering domains that are typographically similar to legitimate ones to deceive users.

5. What’s the difference between prepending and pretexting?

Pretexting involves creating a fabricated scenario to manipulate someone into giving away sensitive information. Prepending is more technical and involves manipulating digital files or links to appear legitimate.

6. How can one defend against prepending attacks?

Preventing prepending attacks involves a combination of technological measures like advanced spam filtering, endpoint protection, and regular patching, as well as educating users to be cautious with email attachments and links.

7. What are the consequences of falling for a prepending attack?

The impact can range from financial loss and data exfiltration to legal consequences due to compliance violations. It can also harm an organization’s reputation and lead to loss of customer trust.

8. Are there any real-world examples of prepending attacks?

Yes, there have been several documented cases of prepending attacks. These attacks often target financial institutions, government agencies, and large corporations, but individuals are also at risk.

9. How does prepending compare to other cyber security techniques?

Prepending is a unique form of cyber attack that relies on both technical trickery and human error. While it may share some similarities with other techniques like typosquatting or pretexting, it has its own set of challenges and countermeasures.