CVE-2021-31319 : Exploit Details and Defense Strategies

Telegram Android <7.1.0 (2090), Telegram iOS <7.1, and Telegram macOS <7.1 are affected by an Integer Overflow in the LOTGradient::populate function of their custom fork of the rlottie library. A remote attacker might be able to access heap memory out-of-bounds on a victim device via a malicious animated sticker.

Understanding CVE-2021-31319

This CVE relates to an Integer Overflow vulnerability in the LOTGradient::populate function used in Telegram Android, iOS, and macOS versions below specified versions.

What is CVE-2021-31319?

CVE-2021-31319 exposes users of affected Telegram platforms to potential remote attacks through a specially crafted animated sticker, leading to unauthorized access to heap memory.

The Impact of CVE-2021-31319

The security flaw enables threat actors to exploit heap memory out-of-bounds on vulnerable devices, posing a significant risk to user data confidentiality and device integrity.

Technical Details of CVE-2021-31319

This section delves into the specifics of the vulnerability found in Telegram's implementation.

Vulnerability Description

The Integer Overflow in LOTGradient::populate function facilitates the unauthorized access of heap memory through a crafted animated sticker, allowing a remote attacker to compromise victim devices.

Affected Systems and Versions

Telegram Android versions prior to <7.1.0 (2090), Telegram iOS versions before <7.1, and Telegram macOS versions before <7.1 are susceptible to this security issue.

Exploitation Mechanism

A malicious animated sticker can trigger the Integer Overflow in the LOTGradient::populate function, leading to heap memory corruption and potential out-of-bounds access.

Mitigation and Prevention

Protecting systems against CVE-2021-31319 requires immediate mitigation steps and long-term security practices.

Immediate Steps to Take

Users should update their Telegram applications to versions above 7.1.0 (2090) on Android, 7.1 on iOS, and 7.1 on macOS to mitigate the risk of exploitation.

Long-Term Security Practices

Deploying security updates promptly, exercising caution while interacting with shared stickers, and staying vigilant against potential threats can enhance overall system security.

Patching and Updates

Regularly check for and apply security patches provided by Telegram to address known vulnerabilities and strengthen the resilience of the messaging platforms.