Showing posts with label IDOR. Show all posts
Showing posts with label IDOR. Show all posts

Thursday, 26 March 2020

Stealing videos from vlc

VLC for iOS was vulnerable to an unauthenticated insecure direct object reference (IDOR) which could allow a local attacker to steal media from the storage by just navigating to the source URL/IP.

This was possible by abusing a functionality in the iOS application for VLC, which allows a user to share files with others over WiFi. This can be simply done by enabling "Network > Sharing via WiFi" and the web-server for this functionality works on port 80(http) protocol.

Technical analysis:
Let's assume a scenario where Bob & Alice are sharing a video over the WiFi using vlc-iOS, Eve could perform this attack by crawling the source IP address of Bob which would list the URL's of the videos shared between Bob & Alice.

Having said that, navigating to those URL's Eve could simply steal the video without Bob's knowledge which successfully leads to unauthenticated IDOR. 

In the below image, Bob's IP is and the hierarchy of stored videos in Bob's phone would look like,

Such things can be crawled via burpsuite or you can use python scrapy to extract the URL's from the host and download the videos.

Mitigation from VLC Security team:
They implemented a user-friendly authentication mechanism on VLC iOS web server for WiFi Sharing. Passcode authentication is enabled when VLC's passcode setting is enabled and the user uses the passcode that he set in VLC's settings to log into Wifi Sharing.

This was reported on 2nd Jan 2019 and patched on 10th Feb 2020 whereas fixed version was publicly released in March 2020. Post mitigation VLC published an advisory for this which you can view here. Aside this issue was accepted for bounty on The Internet.

Update Friday, 22 May 2020: Advisory from VLC Security[1]

Friday, 13 December 2019

IDOR in Power Service

One of the India's leading power supply company named, Adani Power Limited  is the power business subsidiary of Indian conglomerate Adani Group. A subdomain was vulnerable to IDOR (Insecure Direct Object Reference) which could allow attackers to view bills of any users across India. The bill include details such as Name, Address, Bill Amount, Unit rate, Pervious bill details etc.

I found this vulnerability while using one of their service.

Vulnerable URL:

The parameter `TXTCANO` in the above URL contains 9 random digits which can be predicted, having said that, changing the value of that parameter can allow attackers to view bills of any other users. (Proof Of Concept)!

Chaining bugs - (Viewing Bills to Account Takeover)

If the users are not registered under Adani MyAccount. The bill obtained using the above method contains two important details
i.e. Account number and Meter Number using which an attacker could register users account to perform any fraudulent activity.

It was also observed that when you navigate to the registration page and provide the valid "Account Number" and "Meter Number" the MSISDN associate to that account is also disclosed. (Proof Of Concept)!

PS: The registration process sends an OTP to the mapped MSISDN but it was also identified that there is no rate limiting hence performing a brute-force attack would help attackers to find actual OTP or attackers could simply edit MSISDN and insert their own to get OTP.

Hence attacker now have personally identifiable information (PII) of end user i.e. Name, Address, Phone Number and other details in bill. Such information can aid attackers in conducting targeted attacks such as vishing, information gathering via SMS, attempting to steal payment information by impersonating the actual service provider via SMS or telephonic calls.

As per their about page there are 2.9 million users of Adani Electricity.

Timelines: The vulnerability was responsibly reported to Adani Electricity via group[.]csoc[at]adani[.]com on 9th Nov 2019 and was patched without any acknowledgement on 11th December 2019.