“If it ain’t broke, don’t fix it” is absolutely a sentiment observed by cyber-threat actors. Of course, many are capable of incredibly technically sophisticated intrusions, but they also rely on rudimentary techniques. One is domain redirection: forwarding users from a legitimate, benign online domain onto something malicious.   

This type of attack is easy. By exploiting basic vulnerabilities in websites or web applications, threat actors can reroute users to malicious and spammy advertisements or fake news websites. They can also serve them malware, or, most commonly, harvest their credentials. 

Domain redirection attacks present an obvious risk to individuals and companies, as ReliaQuest saw firsthand in recent attack involving fake Microsoft logins. Fortunately, there are ways to protect websites and steer internet users down the right road.  

Open Redirect Vulnerabilities: The Attacker’s Signpost

Open redirect vulnerabilities are commonplace, affecting a wide variety of organizations. But they often fly under the radar of security teams. A web application fails to validate input from an untrusted user (including query strings generated from form data) and you end up with an entry route for threat actors to manipulate without much effort.  

Why are these flaws so common? One reason is the prevalence of unknown or managed infrastructure. But poor vulnerability-management practices can also factor in. If you don’t know an asset exists—or don’t have a designated body to manage it—how can you know whether that asset has a flaw that needs fixing? This is particularly relevant for companies with a large digital footprint and a lack of visibility and robust management of assets.  

The Real Risks of Redirection

A threat actor typically exploits a vulnerable website or application to add credibility to their phishing websites. Many internet users will visit an exploited site and see only a legitimate, benign domain, unaware they’ve been redirected. This probably won’t directly affect the functionality of the legitimate application. But think about the legitimate company behind it; their reputation and credibility are at risk, and they could face financial losses or regulatory measures.  

For the hapless website visitor, the risk is a significant one. Their credentials, personally identifiable information, or financial details could be breached.  

Figure 1: Example of domain redirection attack steps image

Figure 1: Example of domain redirection attack steps 

ReliaQuest has frequently observed malicious actors redirecting innocent online users, and the end destination is often phishing pages. Many of these phishing campaigns are spoofing fake Microsoft landing pages. Exploitation of the original, legitimate domain usually goes undetected by email security solutions because of the original, trusted site’s safe reputation. 

Fake Microsoft Webpage Fast-Tracks Redirection

The domain apiservices.krxd[.]net presents itself, on first glance, as a legitimate domain owned by software and marketing company Salesforce. It’s even appeared in the top 100,000 most visited global websites. And, on initial inspection with open-source tools, the domain did seem to be benign. 

But several users of OSINT platforms called the site illegitimate, and they were right. Attacks connected to this domain followed this route: 

  1. A user mistakenly clicks a link within krxd[.]net and that seemingly benign is ignored by security solutions.  
  2. The user is directed to hxxps://apiservices.krxd[.]net/click_tracker/track?…
  3. The user is further redirected to this attacker-controlled phishing domain: hxxps://techadda.co[.]in/jw//firstname.lastname/…
  4. If the latter site is flagged by a security provider (several providers regard it as malicious and associated with phishing), the attack chain ends here. But for users in an environment without adequate security solutions, the redirect goes unnoticed, as the original domain appeared benign. 
  5. The visitor is presented with a fake Microsoft login page, beckoning them to log in, and thus the motive behind the redirection is revealed: harvesting user credentials. 
Figure 2: Fake Microsoft login page image

Figure 2: Fake Microsoft login page

Big Footprints, Opaque Assets Invite Attacks

Open redirect vulnerabilities—which of course, can lead to a domain redirection attack—present a threat to any company, regardless of sector, region, or maturity level.  

But certain organizations will, undoubtedly, be more susceptible: those with larger digital footprints and/or those whose assets are not fully known or managed. Asset ambiguity can crop up when organizations expand, through implement new infrastructure. 

This is particularly problematic when a website or application administrator leaves an organization and fails to hand over their responsibilities. Unmanaged or unaccounted for assets can easily lead to vulnerabilities and misconfigurations going unaddressed. 

Susceptible Sectors

To assess which sectors are most susceptible to redirection attacks, ReliaQuest identified 30 known websites that have confirmed redirect vulnerabilities. Within our alert repository, we identified customers whose employees had viewed a redirected phishing domain between August 2022 and August 2023 originating from this technique. (They didn’t necessarily mistakenly input their credentials, but they did view the website.) The result (see Figure 3) isn’t a comprehensive view of the risk posed by redirection vulnerabilities, but it implies which sectors will most likely be phished via this technique.  

Figure 3: Average number of viewed websites with redirect vulnerabilities, by website owner’s sector image

Figure 3: Average number of viewed websites with redirect vulnerabilities, by website owner’s sector 

Construction companies are popular social-engineering targets; they use sub-contractors and suppliers heavily, typically handling many high-value payments that invite financial crime via business email compromise or alternative attacks. Other vulnerable sectors are public administration, and finance and insurance. 

Credential Theft Greenlights Account Takeover

The motive behind many redirection attacks is attaining online account credentials. Stolen credentials can lead to account takeover (ATO) and have a huge impact across all sectors and regions. ATO is one of the primary points of entry for attacks by cybercriminals and nation-state threat actors alike. A big percentage of ATO leads to financial fraud or exploitation, sale of the accounts to other actors looking to commit fraud, or wider social engineering targeting the owner of the account.  

Countering Domain Redirection: Take Back Control

One half of the equation to mitigating domain redirection is website security. Here are just a couple of aspects you should consider:  

  • A responsible website owner knows their assets. You should create an inventory of external-facing applications, and routinely assess assets through a vulnerability remediation program. Patch vulnerabilities, remediating the riskiest first.  
  • Consider whether each external-facing application requires a redirect. There are valid reasons to track outbound links, but additional design considerations are required to deter abuse.  
  • If a redirect is needed, consult a predefined list of URLs to prevent arbitrary malicious destinations from being inserted. 
  • If redirection based on user input is required, limit which mechanisms can be used in the redirection. Restricting input to http or https URLs, for instance, can help limit the risk associated with certain types of files, such as malicious JavaScript. 
  • Use web application firewalls (WAFs) to direct malicious actors away from websites. A WAF protects websites against many common types of attacks, and some solutions also offer security reports highlighting important data, such as ongoing site traffic. This provides an opportunity to monitor traffic for significant declines, which is a key sign of a domain redirection attack. 

The other half of the equation comprises user security. For example: 

  • Ensure that employees using any external login pages must submit to two-factor authentication (2FA), which minimizes the chance of a stolen credential being used to access corporate systems. 
  • Implement an email security solution and configure it to quarantine malicious emails; such tools often prevent phishing emails from reaching the end user, but the messages may be delivered if the confidence rating is low. 
  • Train staff to identify suspicious activity. Ensure they verify the URL whenever visiting a sign-on portal. 

Stay ahead of potential threats to your organization with ReliaQuest GreyMatter Digital Risk Protection. Our technology scans the open, deep, and dark web for early warning signs of risk to your business, such as social media and email compromise, exposed credentials, and more. Automated playbooks also help to speed up the remediation process.