Dropbox 6.4.14 DLL Hijacking
Posted on 27 July 2016
Aloha, Summary Dropbox Installer for Windows contains a DLL hijacking vulnerability that could allow an unauthenticated, remote attacker to execute arbitrary code on the targeted system. The vulnerability exists due to some DLL file is loaded by 'DropboxInstaller.exe' improperly. And it allows an attacker to load this DLL file of the attackeras choosing that could execute arbitrary code without the user's knowledge. Affected Product: Dropbox 6.4.14 and prior versions Tested on: Windows 7 Impact Attacker can exploit this vulnerability to load a DLL file of the attacker's choosing that could execute arbitrary code. This may help attacker to Successful exploit the system if user creates shell as a DLL. Vulnerability Scoring Details The vulnerability classification has been performed by using the CVSSv2 scoring system (http://www.first.org/cvss/ <https://hackerone.com/redirect?signature=273a575a933df15fb4c18a77b13c0f4949de2011&url=http%3A%2F%2Fwww.first.org%2Fcvss%2F> ). Base Score: 7.2 (AV:L/AC:L/Au:N/C:C/I:C/A:C) More Details: For software downloaded with a web browser the application directory is typically the user's "Downloads" directory: see https://insights.sei.cmu.edu/cert/2008/09/carpet-bombing-and-directory-poisoning.html <https://hackerone.com/redirect?signature=21fd84ec7a888f372e2663aeb1ea24c253da2958&url=https%3A%2F%2Finsights.sei.cmu.edu%2Fcert%2F2008%2F09%2Fcarpet-bombing-and-directory-poisoning.html> , http://blog.acrossecurity.com/2012/02/downloads-folder-binary-planting.html <https://hackerone.com/redirect?signature=8e7de715fadc691b5fbc9d46f8bc6b0def63a540&url=http%3A%2F%2Fblog.acrossecurity.com%2F2012%2F02%2Fdownloads-folder-binary-planting.html> and http://seclists.org/fulldisclosure/2012/Aug/134 <https://hackerone.com/redirect?signature=a86c271e4c4a984723abef934bc5f94125458dc6&url=http%3A%2F%2Fseclists.org%2Ffulldisclosure%2F2012%2FAug%2F134> for "prior art" about this well-known and well-documented vulnerability. If an attacker places malicious DLL in the user's "Downloads" directory (for example per "drive-by download" or "social engineering") this vulnerability becomes a remote code execution. Proof of concept/demonstration: 1. Create a malicious PGPmapih.dll file and save it in your "Downloads" directory. 2. Download 'DropboxInstaller.exe' from https://www.dropbox.com/downloading and save it in your "Downloads" directory. 3. Execute .exe from your "Downloads" directory. 4. Malicious dll file gets executed. Informed Vendor: Yes Fixed Version: TBA Please assign a CVE ID. Chao!! Himanshu Mehta
