The problem lies in the FCKEditor rich text editor, which is installed with ColdFusion 8, Adobe said on its security blog. Adobe also listed in its warning three steps that could in the meantime mitigate an attack.
FCKEditor is an open-source application that handles file uploads and file management, but the feature is supposed to be disabled in the version embedded on a ColdFusion server, wrote John Mason, a ColdFusion consultant who writes a blog called CodFusion.
In some cases, the connector that enables the feature is left on.
"If left on, this means a hacker might be able to directly call the file manager system to upload files and take control of the server," Mason wrote. "FCKEditor has had some history on being exploited by this type of attack."
The SANS Internet Storm Center, which monitors security threats, said it had seen a "high number" of Web sites running ColdFusion that had been compromised.
"The attacks we've been seeing in the wild end up with inserted <script> tags into documents on compromised Web sites," wrote Bojan Zdrnja of the Internet Storm Center. "As you can probably guess by now, the script tags point to a whole chain of web sites which ultimately serve malware and try to exploit vulnerabilities on clients."
Zdrnja wrote on theInternet Storm Center's blog that there appear to be two attack vectors. ColdFusion version 8.0.1 installs a vulnerable version of FCKEditor, which can be directly exploited and allow a hacker to upload arbitrary files.
Other third-party applications also use FCKEditor, such as CFWebstore, which is an e-commerce application for ColdFusion, Zdrnja wrote. CFWebstore has also been exploited in the attacks, he wrote.