Cybersecurity vulnerabilities are an unfortunate reality for most modern web servers. A common finding in vulnerability scans is the use of plain-text, form-based authentication on admin login pages or other sensitive areas of the application.
This exposes usernames and passwords to potential snooping on the network. While fixing this issue may seem intimidating, a layered security approach can dramatically reduce risks without needing to overhaul legacy systems right away.
Why Plain Text Authentication is a Problem
Plain text authentication simply means sending usernames and passwords from the browser to the server without encryption. This allows the traffic to be intercepted by attackers on an insecure network. There are two primary risks this introduces:
Sniffing User Credentials
A bad actor with access to the same network could use a packet sniffer to extract usernames and passwords as they are transmitted between client and server. They can then use these credentials to gain unauthorized access to the application.
Session Hijacking
Even if the username and password are protected later by encryption, sending them initially in plain text opens the door to man-in-the-middle (MITM) attacks. An attacker can steal the session cookie after credentials are validated and bypass login altogether.
Both risks allow unauthorized application access and data theft. Legacy web apps often use plain text authentication through inertia, but modern cryptography approaches completely mitigate these issues when implemented properly.
Balancing Security Priorities
However, for many organizations with legacy infrastructure, a full overhaul of all systems to enable encrypted protocols like HTTPS is an insurmountable task in the short term. Budget, technical debt, fragile legacy codebases, and inconsistent tooling can all block major architectural pivots.
The key is taking a pragmatic, risk-based approach. Enable encryption where possible, but also layer on compensating controls without needing to boil the ocean early on. Every improvement pushes the needle toward more “acceptable” and manageable risks given the constraints of the environment.
Hardening Plain Text Authentication
Consider starting with these controls to reduce exposure:
Network Segmentation
Isolate insecure systems like legacy web servers into their own security zones with tightly limited access:
- Utilize VLANs to group legacy assets away from more trusted devices
- Leverage internal firewalls to restrict traffic between zones
- Disable routing from the legacy application subnet to other internal assets
This protects other servers if the web app is compromised. Limit administrative access to empower only select users to even reach the vulnerable systems.
IP Allowlists
White-list permitted client IPs that can send requests to legacy web servers:
- Monitor source IPs of all requests in proxy and server logs
- Block unused ranges at the firewall level
- Prevent lateral movement with allowlists rather than relying solely on VLAN segmentation
While IP lists are not a perfect defense, they dramatically raise the difficulty for external parties to scan and attack.
Rotate Shared Credentials
Change admin passwords regularly across all legacy systems and user accounts:
- Enforce complex passwords even if still transmitting in plain text
- Prompt frequent password changes through your identity provider
- Use randomized passwords in code configuration files and scripts
- Reset SSH keys used for server administration
This frustrates lateral movement and requires an attacker to re-compromise even if they gain an initial foothold.
Carefully Manage Vendor Access
Audit third parties with potential access to vulnerable systems:
- Review data access of cloud providers or contractors
- Isolate connectivity through intermediate “jump” boxes
- Disable accounts when access is no longer needed for engagements
- Log provider activity while engaged in auditing
A third-party breach often enables lateral movement into legacy infrastructure not exposed directly to the internet. Manage this privilege cautiously.
The Path Forward
These controls provide compensating rigor while charting a path to more substantial modernization efforts. Scoped encryption, tokenization, and application firewalls are all mid-term projects to consider on the roadmap.
Wrapping at-risk systems in well-rounded protections aligned with business constraints, even if imperfect, allows for security wins while the long process of modernization marches steadily forward. Small improvements drive real risk reduction.
Specific Steps to Solve a Plain Text Auth Finding
Now let’s discuss concrete methods to remediate a plain text authentication finding during a web application security scan:
Is the Finding A False Positive?
First, verify this is truly a finding that needs resolution. Especially with IP-based hosts rather than DNS entries, occasional scan engine misinterpretations happen:
- Confirm the path identified is legitimately passing credentials in plain text
- Review code or sniff traffic manually to validate
- Consider risk context since not every informational issue needs immediate fixing
Document evidence if opting to dismiss a finding as a false positive.
Enable Encryption on The Channel
For confirmed plain text auth issues, implementing HTTPS should be a high priority remedy.
Obtain a Trusted Certificate
Install an SSL/TLS certificate from a respected public certificate authority to enable transport encryption:
- Purchase and validate the certificate using your hostname
- Install certificate on the web server and intermediate systems
- Redirect HTTP to HTTPS in your application code to enforce
This encrypts sessions without needing to modify application logic.
Manage Certificate Errors
HTTP:// URLs may still appear externally or internally even after HTTPS deployment. Root causes include:
- Hard-coded links stored in databases or code
- Old bookmarks saved by users
- Non-production URLs in testing/QA environments
Monitor certificate errors in logs and correct outdated HTTP references.
Harden Authentication Systems
Enabling HTTPS secures credentials in transit, but further hardening is possible:
Migrate to OAuth or SSO
Consider token-based authentication flows to avoid sending credentials at all:
- OAuth relies on access tokens with limited privilege
- SSO uses federated identity without resending passwords
This more thoroughly addresses risks related to intercepting user credentials.
Mask Passwords Fields
Another technique is masking passwords as users type them in login forms:
- Mask password input with asterisks or circles
- Disable copy/paste on fields
This reduces leakage if credentials escape the application, such as through screenshots or shoulder surfing.
More Unique Usernames
In some legacy systems, standard admin usernames pose issues if exposed:
- Map multiple usernames to the admin role
- Obscure account names away from labels like “administrator”
- Automatically expire dormant accounts
This requires attackers to guess credentials rather than relying on a known admin user existing.
Over time, decommission legacy authentication by phasing in modern identity platforms across your application portfolio. But in the short term, pragmatic solutions significantly reduce your exposure to plain text authentication risks commonly flagged in vulnerability reports.
Conclusion
In summary, plain text authentication on web applications is an urgent cybersecurity concern but not always straightforward to remediate completely. Encryption should be prioritized as a first step, but compensating controls also play a key role, especially for legacy systems,
A balanced, risk-based approach accounts for technical and business constraints while meaningfully improving defenses. Over time continued modernization reduces security gaps, but multiple improvements can drive risk reduction today even if legacy technology remains in place for a while longer.
