All vulnerabilities
CRITICALInfraexploited in the wildcurated

CVE-2023-34362

Progress MOVEit · Progress MOVEit Transfer

Summary

CVE-2023-34362 is the specific flaw behind one of the largest data-theft campaigns in history: an unauthenticated SQL-injection vulnerability in Progress MOVEit Transfer, a managed file-transfer application. It let an attacker reach and manipulate the backend database with no login at all. The Cl0p ransomware gang exploited it as a zero-day from late May 2023, using it to plant a web shell and steal files from thousands of organizations at once. This page covers the vulnerability itself; the mass-extortion campaign it enabled is documented separately.

How it worked

The flaw was a classic SQL injection. MOVEit Transfer's web application built database queries using attacker-controllable input without properly parameterizing it, so a single crafted, unauthenticated HTTP request could inject its own SQL and read or write the backend database. No credentials were required, which is what made it so dangerous on an internet-facing application.

The injection was only the first step of a chain. Cl0p exploited it as a zero-day, before Progress shipped a patch on 31 May 2023: they used the SQLi to forge a privileged session token, then abused a .NET deserialization flaw to turn that into remote code execution, which let them drop a web shell called LEMURLOOT (disguised as human2.aspx). Driven by crafted X-siLock HTTP headers, the web shell enumerated and stole the stored files, created a hidden admin account named "Health Check Service," and pulled the credentials to connected Azure Blob storage straight out of the database, with Mandiant observing exfiltration within minutes of the shell landing. The two later MOVEit CVEs (CVE-2023-35036 and CVE-2023-35708) were separate SQL-injection flaws found during the post-incident code review, not part of Cl0p's exploit.

The impact

It became one of the largest mass data-theft events on record: roughly 2,770 organizations and more than 95 million individuals affected, including the payroll provider Zellis, Siemens Energy, Schneider Electric, and numerous government entities. The actor, FIN11 (the crew behind the Cl0p brand, also tracked as Lace Tempest), stole data and threatened to leak it rather than encrypting systems, making it pure data extortion, and because MOVEit is used by service providers, the damage cascaded to organizations that never ran it themselves. The full campaign and its lessons are covered on the MOVEit and Clop page.

Why CVE-2023-34362 still matters

It is the archetype of a SQL-injection zero-day in an internet-facing data application being mass-exploited at scale. SQL injection is one of the oldest and most preventable web vulnerabilities, parameterized queries eliminate it, yet it remains catastrophic when it lands in the wrong place, a file-transfer app holding everyone's most sensitive files. The lessons: parameterize every database query and never build SQL from untrusted input, security-test and pentest internet-facing data apps before they hold sensitive data, patch them on the fastest possible SLA, and hunt for web shells after any such flaw. The broader managed-file-transfer-honeypot lesson is on the Clop campaign page.

How to fix it

  • Patch MOVEit to the fixed version immediately (and the follow-on CVEs found afterward), and take the server offline if you cannot patch fast.
  • Hunt for the LEMURLOOT web shell (`human2.aspx`) and the "Health Check Service" admin account, assume the database contents were stolen, and rotate stored credentials and connected-storage keys.
  • Notify affected downstream parties, since a shared file-transfer product means your breach is your customers' too.

How to avoid it

  • Parameterize every database query and never build SQL from untrusted input; SQL injection is old and entirely preventable.
  • Treat internet-facing managed file-transfer apps as high-risk: minimal exposure, fast patching, segmentation, and web-shell monitoring.
  • Minimize and purge the data these systems hold, and watch vendor advisories for active zero-day exploitation.
  • Security-review and pentest internet-facing data apps before they hold sensitive files.

References

Related vulnerabilities

All Infra →