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Exposed web services

Description

The systems WSDL file contains sensitive information and is exposed to a larger audience than required.

Impact

  • Obtain information from the application services.
  • Expand the attack surface.

Recommendation

Restrict access to /_vti_bin resource to unauthorised users.

Threat

Anonymous attacker from the Internet.

Expected Remediation Time

⌚ 30 minutes.

Score

Default score using CVSS 3.1. It may change depending on the context of the vulnerability.

Base

  • Attack vector: N
  • Attack complexity: L
  • Privileges required: N
  • User interaction: N
  • Scope: U
  • Confidentiality: L
  • Integrity: N
  • Availability: N

Temporal

  • Exploit code madurity: X
  • Remediation level: X
  • Report confidence: X

Result

  • Vector string: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:X/RL:X/RC:X
  • Score:
    • Base: 5.3
    • Temporal: 5.3
  • Severity:
    • Base: Medium
    • Temporal: Medium

Code Examples

Compliant code

Restrict the access to the vti_bin resource only to authorized users

 <location path="_layouts">
<system.web>
<authorization>
<deny users="?" />
</authorization>
</system.web>
</location>
<location path="_vti_bin">
<system.web>
<authorization>
<deny users="general"/>
</authorization>
</system.web>
</location>

Non compliant code

The WSDL does not restrict access to the vti_bin resource

 <location path="_layouts">
<system.web>
<authorization>
<deny users="?" />
</authorization>
</system.web>
</location>
<location path="_vti_bin">
<system.web>
<authorization>
<deny users=none />
</authorization>
</system.web>
</location>

Requirements