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EvilVideo Exploit: Telegram Zero-Day Vulnerability Allows Disguised APK Attacks

 

A recent zero-day vulnerability in Telegram for Android, dubbed ‘EvilVideo,’ has been exploited by attackers to send malicious Android APK payloads disguised as video files. This significant security flaw was first brought to light when a threat actor named ‘Ancryno’ started selling the exploit on June 6, 2024, on the Russian-speaking XSS hacking forum. 

The vulnerability affected Telegram versions 10.14.4 and older. ESET researchers discovered the flaw after a proof-of-concept demonstration was shared on a public Telegram channel, allowing them to analyze the malicious payload. They confirmed that the exploit worked on Telegram v10.14.4 and older, naming it ‘EvilVideo.’ The vulnerability was responsibly disclosed to Telegram by ESET researcher Lukas Stefanko on June 26 and again on July 4, 2024. Telegram responded on July 4, indicating that they were investigating the report. 

Subsequently, they patched the vulnerability in version 10.14.5, released on July 11, 2024. This timeline suggests that threat actors had at least five weeks to exploit the zero-day vulnerability before it was patched. While it remains unclear if the flaw was actively exploited in attacks, ESET shared a command and control server (C2) used by the payloads at ‘infinityhackscharan.ddns[.]net.’ BleepingComputer identified two malicious APK files using that C2 on VirusTotal that masqueraded as Avast Antivirus and an ‘xHamster Premium Mod.’ 

The EvilVideo zero-day exploit specifically targeted Telegram for Android. It allowed attackers to create specially crafted APK files that, when sent to other users on Telegram, appeared as embedded videos. ESET believes the exploit used the Telegram API to programmatically create a message showing a 30-second video preview. The channel participants received the payload on their devices once they opened the conversation. 

For users who had disabled the auto-download feature, a single tap on the video preview was enough to initiate the file download. When users attempted to play the fake video, Telegram suggested using an external player, which could lead recipients to tap the “Open” button, executing the payload. Despite the threat actor’s claim that the exploit was “one-click,” the multiple clicks, steps, and specific settings required for a successful attack significantly reduced the risk. ESET tested the exploit on Telegram’s web client and Telegram Desktop and found that it didn’t work on these platforms, as the payload was treated as an MP4 video file. 

Telegram’s fix in version 10.14.5 now correctly displays the APK file in the preview, preventing recipients from being deceived by files masquerading as videos. Users who recently received video files requesting an external app to play via Telegram are advised to perform a filesystem scan using a mobile security suite to locate and remove any malicious payloads.

GravityRAT: ESET Researchers Discover New Android Malware Campaign


ESET researchers have recently discovered a new Android malware campaign, apparently infecting devices with an updated version of GravityRAT, distributed via messaging apps BingeChat and Chitaco. The campaign has been active since August 2022.

According to ESET researcher Lukas Stenfanko who examined a sample after getting a tip from MalwareHunterTeam, it was found that one of the noteworthy new features seen in the most recent GravityRAT version is the ability to collect WhatsApp backup files.

GravtiRAT

A remote access tool called GravityRAT has been used in targeted cyberattacks on India since at least 2015 and is known to be in use. There are versions for Windows, Android, and macOS, as previously reported by Cisco Talos, Kaspersky, and Cyble. However it is still unknown who is the actor behind GravityRAT, the group has been internally defined as SpaceCobra.

Although GravityRAT has been active since at least 2015, it only began specifically focusing on Android in 2020. Its operators, 'SpaceCobra,' only employ the malware in specific targeting tasks.

Current Android Campaign

According to ESET, the app is delivered via “bingechat[.]net” and other domains or distribution channels, however, the downloads require invites, entering valid login information, or creating a new account.

While registrations are currently closed, this method only enables the threat actors to distribute the malware to targeted users. Additionally, accessing a copy for analysis becomes more difficult for researchers. 

Upon installation on the target's smartphone, the BingeChat app makes dangerous requests for access to contacts, location, phone, SMS, storage, call records, camera, and microphone.

Since these are some typical permissions asked of the users for any instant messaging apps, the malicious app goes unsuspected.

The program provides call records, contact lists, SMS messages, device location, and basic device information to the threat actor's command and control (C2) server before the user registers on BingeChat.

Along with the aforementioned records, files, and document files of jpg, jpeg, log, png, PNG, JPG, JPEG, txt, pdf, xml, doc, xls, xlsx, ppt, pptx, docx, opus, crypt14, crypt12, crypt13, crypt18, and crypt32 types, have also been compromised.

While SpaceCobra’s malware campaign is mainly targeting India, all Android users are advised to refrain from downloading APKs anywhere other than Google Play and be very careful with potentially risky permission requests while installing any app.