Horizon Alert
Summary of the vulnerability and why it matters
A critical vulnerability has been identified in widely used XML parsing libraries within http4s-scala-xml, potentially exposing applications to significant risks. When processing untrusted XML data, affected systems may be vulnerable to attacks that could lead to the disclosure of sensitive local files, unauthorized access to internal network resources, or denial of service. The primary concern is to confirm if our systems utilize these specific vulnerable components for handling external XML inputs, as the library is commonly used for internet-facing web services and APIs.
- XML parsing flaw allows data theft or system disruption.
- Affects common web services processing external XML.
- Confirm relevance and exposure for affected systems.
Attack Path
How an attacker could exploit the issue
An attacker can target web applications that use http4s-scala-xml to process XML data. By sending a specially crafted XML request, an attacker can exploit the XML parser's default behavior, which resolves external entities. This can lead to the disclosure of sensitive files, unauthorized access to internal resources, or disruption of the service.
- Requires network access to the application.
- Triggered by sending a malicious XML payload.
- Risk of data exposure and service disruption.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an attacker to gain access to sensitive information, disrupt services, or target internal network resources by exploiting how XML data is processed. This occurs when an application uses affected http4s-scala-xml decoders to parse untrusted XML, enabling the attacker to inject malicious entities.
- Local files readable by the service process.
- Untrusted XML input is parsed.
- Disclosure of files, SSRF, or DoS.
Operational Fix
Recommended remediation, mitigation, and detection steps
This vulnerability in `http4s-scala-xml` affects applications that parse untrusted XML, potentially leading to data disclosure, SSRF, or denial of service. Ownership of this issue likely falls to the application or service owner responsible for the code using the affected library, in coordination with the platform or infrastructure team managing the underlying services. The first practical step is to identify all services utilizing the library, assess their exposure and criticality, and then plan remediation within a maintenance window, involving vendor coordination if necessary.
- Application owners should own the remediation effort.
- Verify vulnerable library usage and network exposure.
- Plan for remediation based on risk assessment.
