Dxr.axd Exploit Today

Ongoing discussions on underground forums sometimes reference a “new dxr.axd zero-day.” In most cases, these are:

Insecure Direct Object Reference (IDOR).

In the gray hours of a late shift, Alex, a junior security analyst at a mid-sized retail company, stared at a flood of alerts. Most were noise—false positives from marketing tools, a misconfigured printer, someone trying to stream video on a work PC. But one line in the web server log caught his eye: dxr.axd exploit

: DevExpress disputes this, stating that the handler only returns its own client-side library resources (which are already public) and cannot be used to retrieve private server-side code or data.

Tools like SiteLock may flag the r= parameter as vulnerable to blind SQL injection. DevExpress notes that these parameters never reach the database and are sanitized before any query execution in server mode. But one line in the web server log

Scanners often report these for DXR.axd, though they are usually not exploitable:

Azure WAF, Cloudflare, or ModSecurity with Core Rule Set (CRS) can block dxr.axd traversal attacks at the edge. Example ModSecurity rule: Scanners often report these for DXR

Historically, other components related to DevExpress handlers have had confirmed issues:

The attack begins in earnest by fuzzing query parameters. Common parameters associated with dxr.axd include:

That night shift taught Alex that exploits don’t always arrive with flashing red lights. Sometimes they whisper through a forgotten .axd file—and listening closely can save the whole system.