Summary
Xerte Online Toolkits contains an unrestricted file upload vulnerability in its language-pack import functionality. An authenticated user with system permission may upload a crafted archive and request an included PHP file, potentially resulting in remote code execution on the server.
Xerte Online Toolkits contains an unrestricted file upload vulnerability in its language-pack import functionality. An authenticated user with system permission may upload a crafted archive and request an included PHP file, potentially resulting in remote code execution on the server.
Affected context
The vulnerability occurs in Xerte Online Toolkits deployments that allow authorized users to import language packs through the language-pack management functionality. Risk increases when uploaded ZIP archives are insufficiently restricted and extracted files can later be reached through the application's language-loading mechanism.
The vulnerability occurs in Xerte Online Toolkits deployments that allow authorized users to import language packs through the language-pack management functionality. Risk increases when uploaded ZIP archives are insufficiently restricted and extracted files can later be reached through the application's language-loading mechanism.
Exploit preconditions
- Attack surface: Language-pack import functionality, including the upload endpoint and language-file retrieval path
- Required access: Authentication and system permission sufficient to import language packs
- Trigger point: Importing a crafted ZIP archive and requesting a language resource through the language parameter
- Why exploitation is possible: The application may accept an archive containing a PHP-capable
.incfile and make that file accessible for server-side execution
- Attack surface: Language-pack import functionality, including the upload endpoint and language-file retrieval path
- Required access: Authentication and system permission sufficient to import language packs
- Trigger point: Importing a crafted ZIP archive and requesting a language resource through the language parameter
- Why exploitation is possible: The application may accept an archive containing a PHP-capable
.incfile and make that file accessible for server-side execution
Why this happens
The underlying issue is inadequate restriction and validation of uploaded archive contents. Files with executable server-side extensions can be introduced through a feature intended for language resources and subsequently reached through an application-controlled path. This behavior maps to CWE-434: Unrestricted Upload of File with Dangerous Type, because the upload workflow does not sufficiently constrain file types, archive contents, storage location, or execution behavior.
The underlying issue is inadequate restriction and validation of uploaded archive contents. Files with executable server-side extensions can be introduced through a feature intended for language resources and subsequently reached through an application-controlled path. This behavior maps to CWE-434: Unrestricted Upload of File with Dangerous Type, because the upload workflow does not sufficiently constrain file types, archive contents, storage location, or execution behavior.
Potential impact
- An attacker may execute arbitrary PHP code on the application server
- The compromise could expose or alter application data
- The attacker may modify hosted content or application configuration
- Server credentials and connected services could be at risk
- The vulnerability could support persistence or lateral movement, depending on deployment permissions
- An attacker may execute arbitrary PHP code on the application server
- The compromise could expose or alter application data
- The attacker may modify hosted content or application configuration
- Server credentials and connected services could be at risk
- The vulnerability could support persistence or lateral movement, depending on deployment permissions
General mitigation guidance
Mitigation generally focuses on treating language-pack archives as untrusted content and ensuring uploaded files cannot become executable.
Common defensive patterns include:
- Allowing only explicitly approved language-file formats and archive members
- Rejecting executable extensions and unexpected nested paths during archive processing
- Extracting uploads outside web-accessible and server-executable directories
- Serving imported resources through a non-executing content path
- Applying strict archive validation, size limits, and path-traversal protections
- Running the application with least privilege and isolating its filesystem and service permissions
- Reducing trust in user-supplied language parameters through allowlists and controlled resource mapping
Mitigation generally focuses on treating language-pack archives as untrusted content and ensuring uploaded files cannot become executable.
Common defensive patterns include:
- Allowing only explicitly approved language-file formats and archive members
- Rejecting executable extensions and unexpected nested paths during archive processing
- Extracting uploads outside web-accessible and server-executable directories
- Serving imported resources through a non-executing content path
- Applying strict archive validation, size limits, and path-traversal protections
- Running the application with least privilege and isolating its filesystem and service permissions
- Reducing trust in user-supplied language parameters through allowlists and controlled resource mapping
How teams detect issues like this
Detection can combine application, filesystem, and code-level review:
- Use static analysis to identify upload handlers that accept archives without member-type validation
- Review whether extracted files are placed beneath executable or web-accessible directories
- Inspect code for language parameters that resolve directly to user-controlled filenames
- Monitor upload and extraction events for unexpected
.php,.inc, or other executable files - Alert on web requests for newly created language-pack paths and anomalous server-side process activity
- Enforce CI and security policies requiring archive validation, safe extraction, and non-executable upload storage
Automated code-review and software composition tools may help identify related upload and path-handling patterns.
Detection can combine application, filesystem, and code-level review:
- Use static analysis to identify upload handlers that accept archives without member-type validation
- Review whether extracted files are placed beneath executable or web-accessible directories
- Inspect code for language parameters that resolve directly to user-controlled filenames
- Monitor upload and extraction events for unexpected
.php,.inc, or other executable files - Alert on web requests for newly created language-pack paths and anomalous server-side process activity
- Enforce CI and security policies requiring archive validation, safe extraction, and non-executable upload storage
Automated code-review and software composition tools may help identify related upload and path-handling patterns.
