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# Exposing the Sophisticated Cyber Espionage Tool Known as BendyBear

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By [Ryan Olson](https://www.paloaltonetworks.com/blog/author/ryan-olson/?ts=markdown "Posts by Ryan Olson")  
Feb 09, 2021  
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This post is also available in: [日本語 (Japanese)](https://www.paloaltonetworks.com/blog/2021/02/u42-bendybear/?lang=ja "Switch to Japanese(日本語)")

On Tuesday, Unit 42 disclosed the discovery of BendyBear, one of the most sophisticated cyber espionage tools seen to date. It is designed for *extreme* stealth, with features that allow it to evade detection by security products and make it difficult for threat researchers to reverse engineer. Unit 42 published a report with details on the malware's capabilities, "[BendyBear: Novel Chinese Shellcode Linked With Cyber Espionage Group BlackTech](https://unit42.paloaltonetworks.com/bendybear-shellcode-blacktech/)."

BendyBear appears to be a variant of WaterBear, malware used for lateral movement while hiding its activities, due to strong similarities. Other researchers, including [Trend Micro](https://www.trendmicro.com/en_us/research/19/l/waterbear-is-back-uses-api-hooking-to-evade-security-product-detection.html) and [TeamT5](https://blogs.jpcert.or.jp/ja/2020/02/japan-security-analyst-conference-2020-1.html), have attributed WaterBear to BlackTech, a group with links to [the Chinese government](https://www.taiwannews.com.tw/en/news/3991160) that is believed to be responsible for attacks on East Asian governments and technology organizations dating back to at least 2009.

BendyBear uses a modified version of RC4 encryption, which hardens the encryption and makes it more difficult to break its network communications. It also uses polymorphic code that gives the malware chameleon-like abilities: It alters its bytes after runtime execution, making it unreadable, meaningless and extremely difficult to detect. It loads payloads directly into memory, rather than a filesystem, which means it's not leaving behind traditional fingerprints for threat researchers and security products to find. These features make it exceptionally difficult to detect.

Unit 42 has already shared information about BendyBear with trusted government and industry partners, including the Cyber Threat Alliance. That data includes Indicators of Compromise (IoCs) that organizations can use to determine if they've been compromised by BendyBear and also block future attacks.

Palo Alto Networks hopes that the release of this information will shed enough light on BendyBear to make it a far less effective tool for cyber espionage. Still, we urge organizations to remain vigilant against attackers utilizing advanced tactics to remain undetected, as exhibited by the [SolarWinds attacks](https://www.crn.com/news/security/solarwinds-should-have-been-more-vigilant-palo-alto-networks-ceo).

Palo Alto Networks offers protections from the BendyBear attacks outlined in this blog through [Cortex XDR](https://www.paloaltonetworks.com/cortex/cortex-xdr?ts=markdown), as well as its [DNS Security](https://www.paloaltonetworks.com/products/threat-detection-and-prevention/dns-security?ts=markdown), [URL Filtering](https://www.paloaltonetworks.com/products/threat-detection-and-prevention/web-security?ts=markdown) and [WildFire](https://www.paloaltonetworks.com/products/secure-the-network/wildfire?ts=markdown) subscriptions for the [Next-Generation Firewall](https://www.paloaltonetworks.com/network-security/next-generation-firewall?ts=markdown).

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