Flaws in Telegram & WhatsApp on Android Put Data at Risk

App settings combined with Android behavior can put data integrity at risk for WhatsApp and Telegram users.

WhatsApp and Telegram are personal messaging apps that have, between them, more than 1.7 billion users around the world. They are frequently used by political activists, healthcare providers, and businesses around the world because of the security of their always encrypted communications. But recent research shows that there are security vulnerabilities that could open the services to manipulation and data theft for users on Android devices.
In a blog post today, Symantec researchers Yair Amit and Alon Gat discussed a media file jacking flaw in the way that the Android apps store files that the user receives. The researchers note that the flaw isnt in the app code, but in the app logic, specifically where the apps will store files that they receive.
We found the vulnerability in the way on Android that WhatsApp (by default) and Telegram (in a certain setting) can store attachments like photos and audio messages before the user is able to open the original file, says Domingo Guerra, senior director of modern OS security at Symantec.
The trouble is that Android can store files in two locations — internal and external storage. Data in internal storage can only be accessed by the app that stored it. Data in external storage is defined as world readable and writeable — any app or user can read and modify the data.
WhatsApp stores received media files in external storage by default. Telegram uses external storage for its Save to Gallery feature. In both cases, the files are stored to publicly accessible directories.
According to Guerra, there are several kinds of damage that could result from the ability to intercept and manipulate files on an Android device — damage beyond the simple ability to see what sort of files are being sent back and forth between users.
In the
blog post on the vulnerability
, the researchers point out image manipulation, in which faces are changed or individuals inserted into images; audio manipulation, in which a deepfake technology makes it seem an individual is saying something they never actually said; invoice manipulation, in which the amount and payment details in a legitimate invoice are changed to send money into the attackers account; and fake news, in which the material sent out by a legitimate news organization is changed to become inaccurate, as possible harm from media file jacking.
To add to the vulnerabilitys seriousness, You dont have to attack Telegram or WhatsApp for this to happen, says Guerra. A device that already has malware thats monitoring for external storage could be vulnerable to replaced documents.
The apps global footprints mean that the potential impact of these vulnerabilities. For example, Otavio Freire, CTO and president of SafeGuard Cyber, says, In South America two years ago, doctors didnt use WhatsApp to communicate at all. Now, the adoption is 90% of Brazilian doctors who use WhatsApp for daily business.
And Freire says that more companies will be — and should be — using WhatsApp, Telegram, and other messaging apps going forward. Companies that come to WhatsApp have come to it because it has significantly impacted their business processes, he says. They do better marketing. They do better sales. They do better customer service. Thats where the customers are, so if you ignore it, youre not where your customers are.
As for protection against the vulnerabilities, both Guerra and Freire say that some steps will be up the individual device owners — like setting WhatsApp to store files in internal storage and not using the Gallery function of Telegraph.
In addition, Freire points to the importance of saving archival copies of any corporate information transmitted by either app (or other messaging apps). In an era that sees the possibility of deepfakes, they are necessary insurance against unwanted information going out to employees or customers.
Related content:
US Law Enforcement Shuts Down Massive Marketplace for Compromised Servers
Middle East, North Africa Cybercrime Ups Its Game
Financial Firms Face Threats from Employee Mobile Devices
Commercial Spyware Uses WhatsApp Flaw to Infect Phones
WhatsApp: Mobile Phishings Newest Attack Target

Black Hat USA returns to Las Vegas with hands-on technical Trainings, cutting-edge Briefings, Arsenal open-source tool demonstrations, top-tier security solutions, and service providers in the Business Hall. Click for information on the
conference
and
to register.

Last News
▸ ArcSight prepares for future at user conference post HP acquisition. ◂ Discovered: 07/01/2025 Category: security	▸ Samsung Epic 4G: First To Use Media Hub ◂ Discovered: 07/01/2025 Category: security	▸ Many third-party software fails security tests ◂ Discovered: 07/01/2025 Category: security

**Cyber Security Categories**
Google Dorks Database	Exploits Vulnerability	Exploit Shellcodes

CVE List

Tools/Apps

News/Aarticles

Phishing Database

Deepfake Detection

Trends/Statistics & Live Infos

Tags:
Flaws in Telegram & WhatsApp on Android Put Data at Risk