What Is Persistence in Cyber Security? Definition, Techniques & Examples

Ever had a neighbor who just won’t take the hint to leave you alone? When a simple “no solicitors!” sign won’t make them stop ringing your doorbell, you’re dealing with some serious persistence. Well, in the cyber world, persistence has a whole other meaning – and the overly eager neighbor is replaced by sophisticated hackers who make it their mission to stick to your devices like glue.

In cybersecurity terms, persistence refers to malicious techniques that enable access to a system long after an initial compromise. Once criminals sneak through the digital door, persistence gives them the ability to return again and again, no matter how many times you try to kick them out. These crafty infiltration methods are what turn a one-time computer infection into a recurrent nightmare.

In this article, we’ll reveal the secrets behind what makes cyberattacks so stubbornly persistent. We’ll arm you with defense strategies to beat hackers at their own persistent game. And your devices will finally be rid of those persistent pests!

So unplug the doorbell, install some cyber defenses, and get ready to shut the door on persistently pesky malware! Our article will leave hackers working harder than ever just to land that initial foothold, let alone become a long-term thorn in your network’s side.

What Is Persistence in Cyber Security?

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In cybersecurity, persistence refers to the techniques and strategies that enable continued access to a system after the initial point of compromise. Essentially, it is what allows an attacker to maintain their foothold within a network despite efforts to remove them.

Without persistence, a compromise would be limited to the initial breach. An attacker might infiltrate a system through a vulnerability but then lose access when the system is rebooted or patched. Persistence ensures hackers have an ongoing presence that is resistant to such cleanup efforts. It turns an intrusion from a one-time event to a long-dwelling compromise.

Cybercriminals use various persistence mechanisms to essentially implant remote access doors that allow them to sneak back into previously infiltrated networks. Backdoors will be installed or access credentials obtained so attackers don’t have to rerun exploits after being discovered. 

System configurations are altered to enable malware or scripts to automatically restart upon reboot. Ongoing access offers attackers more time to extract data, establish command and control servers, install additional payloads, and cause even greater damages undetected over long periods.

In essence, persistence changes the nature of cyber intrusions from individual incidents to persistent threats that linger, fester, and offer continued opportunities for exploitation. Stopping advanced persistent threats with sophisticated persistence techniques requires special detection and response capabilities to root out and shut down all avenues of access.

Unique Characteristics of Persistent Attacks

Persistent attacks are distinguished from other cyber threats by the following key characteristics:

High Degree of Sophistication

Persistent attacks involve an advanced level of expertise and technological sophistication that is not typically seen in more common cyberattacks. APT actors make use of zero-day exploits, custom-made malware, and advanced evasion techniques to avoid detection and bypass the target’s cybersecurity measures. 

These threat actors are highly skilled and resourced, often engaging specialized technical teams to reconnoiter systems, develop customized malware, and stealthily exploit vulnerabilities.

Focused Targeting

While common cyberattacks are often opportunistic in nature, targeting random victims, Persistent attacks are focused specifically on infiltrating high-value targets such as governments, major corporations, critical infrastructure providers, and defense contractors. 

APT actors conduct thorough research on the target’s infrastructure and employees to enable highly tailored social engineering and exploit specific individuals, systems, and data that further their objectives.

Well-Resourced Threat Actors

Due to their high degree of sophistication and intensive operational requirements, Persistent attacks are usually attributed to well-resourced threat actors such as nation-state intelligence agencies and highly capable criminal organizations. 

These groups invest substantially in developing and acquiring advanced hacking tools and expertise to compromise their intended target through an APT operation. The significant resources dedicated to establishing and maintaining access distinguish persistent attacks from everyday cybercrime.

Long-Term Compromise Objectives

While most cyberattacks aim to penetrate systems, exfiltrate data, and exit undetected in a short period, APT campaigns are characterized by the threat actor’s intent to persist within the target network undetected for an extended duration. 

By maintaining access over long periods, APT actors facilitate gradual exfiltration of sensitive data, continuous surveillance, or the ability to inflict damage at a time of their choosing.

Progressive Attack Stages

A defining feature of Persistent attacks is the structured, multi-stage progression in how the attack unfolds. After carefully selecting targets, threat actors first conduct extensive reconnaissance of the target network and personnel, gathering technical details and patterns of behavior. Next, they craft malware or exploits specifically for the intended targets before compromising select systems and accounts.

Once inside, they take care to expand access privileges and establish resilient command and control channels before pursuing their final objectives, all while taking active measures to avoid detection.

Multiple Entry Vectors

APT actors prepare and stage various vectors to breach the target’s network environment and maintain persistence, including spear-phishing attacks directed at key personnel, watering hole attacks that exploit websites frequented by the target, and compromising third-party suppliers or contractors to leverage trust relationships. By stealthily attacking through multiple vectors, APT actors enhance their chances of success and make their presence much harder to eliminate.

In summary, advanced persistent threats represent one of the most complex and severe cybersecurity challenges faced today due to the high technical expertise, patient operational tempo, diversity of access vectors, and advanced evasion capabilities leveraged by these sophisticated threat actors in pursuing their objectives over extended periods.

How Does the Persistence Method Work?

Persistence methods follow a sequence of infiltration activities that enable advanced hackers to gain a lasting foothold in targeted systems.

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By progressing through key phases – reconnaissance, exploitation, establishing persistence, and acting on objectives – sophisticated threats can transition from outside actors to embedded menace.

1. Reconnaissance

In initial reconnaissance, attackers extensively research the target environment to uncover potential weaknesses. This involves identifying vulnerabilities in external-facing assets like servers, VPN gateways, and remote access systems. Attackers may utilize network scans, open-source research, social engineering, and more to map out accessible targets. Vulnerability assessments pinpoint specific software flaws, misconfigurations, or weak credentials to exploit.

2. Exploitation

With reconnaissance complete, hackers attempt to breach defenses by exploiting known vulnerabilities. Common exploits leverage code injection, buffer overflows, denial of service attacks, and phishing techniques. For example, a hacker may distribute malware by email that triggers remote code execution on a vulnerable server due to a flaw in outdated software. Successful exploitation provides attackers initial access to assets within the target environment – a pivotal first step.

3. Establishing Persistence

To prevent loss of access after exploitation, threat actors quickly trigger persistence mechanisms on compromised systems. This ensures they have enduring access that is resistant to common countermeasures like rebooting servers or patching vulnerabilities. 

Persistence may involve replacing legitimate system files with malware-equipped versions, editing configurations to enable backdoor access, installing automated scripts, or tweaking a cron job to trigger remote commands. Attackers essentially implant remote access to prevent loss of system control after initial infection.

4. Acting on Objectives

Once firmly rooted with persistence in place, the real devastation begins. Hackers now have the time and cover to act on their objectives without victims detecting the ongoing compromise. This may involve deploying ransomware across networks, extracting sensitive data and intellectual property, installing spyware tools, capturing user credentials for financial fraud, corrupting systems, and more.

What distinguishes Persistent attacks is their ability to stealthily pursue larger schemes through persistence, whereas typical threats are short-lived. Their goals may even shift over time as hackers pivot between systems and identify new opportunities.

But understanding their infiltration playbook helps equip defenders with the awareness to harden systems, halt progression through key phases, and prevent advanced persistent threat scenarios from fully unfolding.

What Does Persistence Look Like?

Persistence is a critical component of many cyberattacks.

Let’s walk through an example of what persistence could look like. Imagine an attacker is able to exploit a vulnerability and gain an initial foothold on a victim’s system. The attacker’s access at this point is tenuous – if the system is rebooted, antivirus software is run, or other changes occur, the attacker could lose access.

To establish persistence, the attacker installs a backdoor. One simple way to do this is by using built-in Windows features like scheduled tasks. The attacker creates a scheduled task that executes a command each time the system boots up. For example:

cmd /c “start /b c:\ProgramData\backdoor.bat”

This scheduled task kicks off a new command prompt session in the background and executes a batch script called backdoor.bat that is stored in the ProgramData folder.

What does the backdoor.bat script do? The attacker can customize it to carry out any routine, but a common tactic is adding a new user with administrative privileges:  

net user eviluser “mypassword” /ADD

net localgroup administrators eviluser /ADD

Now, each time the system restarts, this batch script will execute automatically in the background, re-creating the backdoored admin account for the attacker to use. The account even has a password set, so it looks like any other legitimate account to blend in.

This is just one simple method of persistence, but the general idea is that the attacker implants something in the system to maintain access. This could also be achieved via registry edits, DLL hijacking, rootkits, or other techniques.

The challenge for defensive security tools is detecting the activity as malicious since creating user accounts and scheduled tasks are normal administrative functions. Therefore, the attacker’s actions tend to fly under the radar.

Persistence allows an attacker to hide out within the existing software and features of the operating system. Their access becomes embedded in the regular background noise and workflows of the organization. Even if some components like user accounts or files are deleted, the persistence mechanism ensures they are recreated.

This is why persistence is such a priority for attackers – it enables long-term, stealthy access that can be the launching point for lateral movement and data exfiltration.

Common Persistence Methods Used in Cyber Attacks

Attackers have many techniques available to covertly maintain access to compromised systems over extended periods. By achieving persistence, threats can dodge detection and countermeasures in order to pursue larger objectives. 

Common persistence tactics involve camouflaging malware as legitimate processes, editing system configurations to re-enable access, and compromising domain environments.

Misconfiguration Persistence

Vulnerabilities introduced through misconfigurations represent a simple starting point for persistence. Taking advantage of weak credentials, service flaws, or improperly scoped privileges allows recurring system control.

Stored Passwords: Attackers may extract passwords left in configuration files or code repositories to impersonate valid users over and over. Similarly, reusable passwords across environments quickly enable wider access. Properly storing credentials is essential to limiting unauthorized logins.

Service Misconfigurations: By replacing legitimate executables with malware-laden versions, hackers can trigger implants each time operating systems launch certain processes. Modifying services via domain policies, WMI repositories, or startup routines ensures recurring execution. Properly scoping service permissions and accounts prevents privilege escalation.

Malware Persistence

Malware operators often rely on stub implants that re-initiate access despite reboots, patches, or other countermeasures. Stub components evade antivirus tools while kicking off larger malware packages post-compromise. Common hiding spots include Windows startup folders, registries, scheduled tasks, and more. Routine sweeps help uncover suspicious access loops.  

Windows Services Manipulation

Built-in Windows services represent key targets since their automatic re-launch abilities offer natural persistence. By configuring malware as a service, remote access can blend in seamlessly with background system functions. Attackers may extract stored passwords or tweak permissions to hide rogue services undetected. Proper account usage, scoping, and updating deter attacks.

Domain Escalation

Hackers can turn a single system compromise into full domain persistence by utilizing distributed access capabilities. A breach of one low-level asset with local admin rights can enable pivoting to domain controller levels. Password dumping and credential theft then persist access. Compartmentalization, routine resets, and stricter domain controls impede attacks.

In essence, persistence focuses on embedding access so deeply into target environments that short-term countermeasures fail to eliminate threats. By continually reinitiating implants, malware, or backdoors, hackers bypass restrictions that would contain one-time intrusions. Combining tactics ensures recurring execution: services restart implants, domains spread access, and configurations reopen doors.

Some Examples of Persistent Attacks

Persistent Attacks are characterized by their advanced techniques, tactics, and procedures that allow threat actors to gain access to sensitive systems and evade detection for extended periods of time. Here we discuss four major persistent attacks that have been uncovered over the past couple of years:

SolarWinds Attack

The SolarWinds supply chain attack, publicly disclosed in December 2020, is considered one of the most technologically sophisticated cyber espionage campaigns ever detected. Russian foreign intelligence service hackers associated with the APT29 group (also known as Cozy Bear) are believed to be behind this attack.

The attackers compromised software updates for SolarWinds’ Orion network monitoring product, which is used by hundreds of thousands of organizations worldwide. By injecting malicious code into legitimate software updates, the attackers were able to create a backdoor into the networks of SolarWinds customers. 

This is a prime example of a dangerous supply chain attack, where the downstream customers and users of software can be impacted even if they did nothing wrong themselves.

Once the backdoor was in place, the attackers could steal data and distribute additional malware. According to cybersecurity experts, the attackers showed interest in email communications, cybersecurity tools, and settings, as well as various government and policy-related information.

High-profile entities that were impacted include US federal agencies such as the Treasury, Commerce, Energy, and Homeland Security departments. Tech companies like Microsoft, security vendors like FireEye and Malwarebytes, and telecommunications providers were also breached.

The SolarWinds campaign highlighted the risks associated with complex software supply chains. It also demonstrated how advanced persistent threat actors have the patience, resources, and technological capabilities to plan and execute such intricate, stealthy attacks in order to collect intelligence.

Microsoft Exchange Attack

In early 2021, Microsoft reported that a Chinese state-sponsored group named Hafnium was exploiting four previously unknown vulnerabilities in on-premise versions of Microsoft Exchange Server. Hafnium used these vulnerabilities to steal email accounts and data from several US-based organizations. The attack impacted tens of thousands of organizations globally, primarily those using Exchange Server.

Once Hafnium hackers gained access to an Exchange server either with stolen passwords or the exploitation of the Exchange vulnerabilities, they were able to access email accounts and steal data. In some instances, the hackers also deployed web shells for continued access and deployed ransomware on vulnerable servers. Web shells can allow remote administration capabilities.

While the vulnerabilities were patched by Microsoft, many organizations did not patch quickly enough, leading to additional compromises by other APT groups, such as LuckyMouse and Calypso APT, who took advantage of the security flaws after they were publicized. This demonstrates how quickly network vulnerabilities are scanned and exploited at a global scale in today’s era of cyberspace.

SUNBURST Attack on SolarWinds Continues

In the April-May 2021 period, another sophisticated cyberattack campaign was observed targeting government agencies, think tanks, consultants, and non-governmental organizations. This time, APT35 (also called Charming Kitten) was impersonating the USAID and sending spear-phishing emails to gain access to sensitive networks and accounts.

Notably, some of the primary malware used was called Raindrop, which is a module that was part of the SolarWinds attack payload. This provided evidence that yet another APT group associated with the initial SolarWinds compromise was continuing to leverage access and tools to pursue additional cyber-espionage objectives. Specifically, this activity has been attributed to Nobelium, the threat actor behind the SolarWinds attack that is associated with Russia’s foreign intelligence service.

The ongoing Nobelium attacks highlight that advanced persistent threats, especially those carried out by foreign intelligence cyber operators, involve campaigns that pursue long-term access to sensitive networks for stealthy surveillance. Even if one malicious tool is discovered and removed, sophisticated APT actors often have additional ways to maintain their presence on valuable target networks.

APT41 Targets Healthcare, Telecom and Education Sectors

APT41 is a prolific Chinese state-sponsored cyber threat group that carries out state-approved cyber espionage missions as well as financially-motivated intrusions and cybercrime. They have been known to exploit vulnerabilities in popular applications such as Citrix, Redis, and Oracle WebLogic servers to infiltrate networks.

In August 2020, the US Justice Department indicted five Chinese nationals working with a front company called Chengdu 404 Network Technology, which acted as a contractor for Chinese intelligence agencies. The indictment formally charged the suspects with hacking more than 100 businesses and organizations in the US and abroad, including software and gaming companies, universities, think tanks as well as government agencies in various sectors such as healthcare, high-tech manufacturing solar energy.

The scope and scale of victims demonstrate APT41’s ambition to collect data and intellectual property from influential organizations across many geographies and verticals. The group leverages both known vulnerabilities as well as their own malware implants like BACKSPACE, which allows them to persist within networks for long periods while aiming to increase access across connected systems.  

As these examples demonstrate, advanced persistent threat groups continue to present serious cybersecurity challenges given their sophistication, patience, and resources. Organizations need to continue improving their cyber defenses, threat intelligence, and incident response in order to detect and mitigate the impact of Persistent attacks going forward.

Strategies to Protect Against Persistence Attacks in Cybersecurity

Defending against advanced persistent threats requires matching sophisticated hackers’ creativity with robust, multilayered security preparations. Organizations should utilize a defense-in-depth approach across assets, accounts, access points, and activity monitoring to disrupt repeated infiltration efforts.

• Enforce the Principle of Least Privilege

Reducing unnecessary privileges across all systems diminishes openings for persistence mechanisms to take hold. When services, accounts, and credentials only have strictly scoped access that is essential for business functions, advanced exploits have nowhere to sneak in. Enforcement requires thorough asset management and routine entitlement reviews.

• Utilize Standard User Accounts

Ensuring personnel utilize standard accounts for normal daily activities rather than elevated credentials blocks many persistence vectors that rely on high-level compromise. Admin powers should only be temporarily enabled on an as-needed basis to perform specific tasks before returning to standard status. Strict access compartmentalization prevents breaches from spreading internally.

• Implement Identity Threat Detection/Response

As identities represent prime targets for prolonged compromise, securing the identity infrastructure should be prioritized. ITDR solutions introduce robust monitoring of account activities to spot anomalous behaviors indicative of credential misuse, policy violations, and insider threats. Routine threat-hunting sweeps should scan for risks like password leaks, privilege creep, and potential domain escalation avenues.

• Automate Password Hygiene

Requiring complex and unique passwords across all systems and regularly resetting credentials discontinues unauthorized logins before they turn into persistence footholds. Eliminating hardcoded passwords in scripts/services blocks common backdoor access. SSH key management solutions can secure remote connections to prevent credential theft.

• Control and Audit Privileged Access

Adopting privileged access management (PAM) formalizes the process of granting temporary admin access when needed for specific tasks. PAM enables accountability for elevated activities through granular logging while minimizing the duration of enhanced privileges. Secure workflows and credential management contain accidental exposures that open persistence doors.

• Prevent Unwanted Programs

By blocking auto-runs from unexpected directories, establishing tighter file integrity checks, and restricting lateral endpoint connections, malware can be disrupted before escalating internally. Application allowlisting fortifies workstations against untrusted code execution while still permitting vital software.

• Block Anomalous File Writes  

Monitoring attempts to write data to unusual directories outside expected software behaviors spot clandestine activities like credentials scrapers, implant droppers, and rootkits. advanced endpoint security can halt suspected persistence payloads until threats are evaluated.

• Manage Vendor Access

Securing external connections prevents third parties from introducing corrupted files or configurations that pave the way for persistence mechanisms. Vendor-privileged access management (VPAM) strictly governs remote administrative sessions through enhanced monitoring, just-in-time access controls, and activity logging to ensure appropriate usage.

Comprehensive preparation and vigilant monitoring of identities, assets, and activities are essential to catching persistent efforts before they become firmly entrenched. IT teams can take inspiration from advanced persistent threats’ playbooks to implement similarly layered defenses.

Conclusion

And there you have it folks – persistence in cybersecurity broken down. We’ve looked at what it means to stick to it and stay glued to achieving your hacking objectives, even when systems try to shake you off or give you the cold shoulder.

Whether it’s poking and prodding servers until you wheedle your way in or clinging on like a leech to slowly siphon data, persistent threats just don’t know when to pack it in. They’ll keep hammering away until they finally smash through barriers and break open the motherlode of sensitive information they were digging for.

So remember – keep drilling those cyber hygiene practices into your team and bolting down defenses, or you might find persistent naughty hackers making themselves at home in your systems before you can yell “cybercrime doesn’t pay, go breach somewhere else!”

And now, if you want to outsmart the persistent actors and level up your cybersecurity game, check out CCS Learning Academy’s cybersecurity courses. Remember, in cybersecurity, knowledge is power, and a well-placed firewall is just as important as a well-timed dad joke. Happy learning, cyber warriors!

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