HackDig : Dig high-quality web security articles for hacker

cuteRansomware Uses Google Docs as C&C Server

2016-07-15 08:40

Security researchers have discovered a new ransomware family named cuteRansomware that uses Google Docs to store information regarding infected victims.

The origin of this malware seems to be yet another ransomware experiment that was foolishly open-sourced on GitHub a few months back.

cuteRansomware based on open-source ransomware experiment

The project, named my-Little-Ransomware, is an "easy ransomware module base on csharp," as described by its creator, Chinese developer Ma Shenghao.

As it happened with the Hidden Tear and EDA2 projects open-sourced by Turkish security researcher Utku Sen, it didn't take long for crooks to use the my-Little-Ransomware code to create their own versions of ransomware.

The first ones were spotted in mid-June by AVG security researcher Jakub Kroustek, who immediately pointed out that this new ransomware used Google Docs to store its encryption keys.

A few days back, security firm Netskope saw a different ransomware variant, also based on the my-Little-Ransomware GitHub project. They named this one cuteRansomware because of the crook's usage of the "cuteRansomware" string all through his code. [UPDATE: We were told that cuteRansomware infections actually first appeared in mid-June as well.]

cuteRansomware seems to be targeting Chinese-speaking users only

From the get-go, researchers spotted that all code comments were written in Chinese, and so was the ransom note, hinting at a limited distribution model that at the time targeted only Chinese-speaking users.

After a closer look at the code, as with the version spotted by the AVG researcher, this variant also used a Google Docs form as its C&C server.

cuteRansomware was infecting computers, generating the RSA encryption key, and then sending the key to the Google Docs form via HTTPS.

Researchers noted that, compared to the original GitHub project, this version of the ransomware targeted for encryption a smaller number of files, which is quite peculiar since this reduces the ransomware's ability to do damage on infected systems.

cuteRansomware uses .encrypted file extension (in Chinese)

Affected users can spot cuteRansomware infections by the lack of a ransom screen. cuteRansomware only shows a popup text file with the ransom note written in Chinese. Additionally, all encrypted files will have the ".encrypted" (in Chinese) extension added at the end.

"At the time of writing this blog, the form was still available on the Google Docs," said Netskope's Umesh Wanve. "[W]e have notified Google’s security team about this."

Malware that hides its C&C servers on cloud services is not new by any means. Last December, FireEye discovered the LOWBALL backdoor trojan, which used Dropbox as a C&C server.

Comparison between GitHub project and cuteRansomware code
Comparison between GitHub project and cuteRansomware code


Source: lmths.043605-revres-c-c-sa-scod-elgoog-sesu-erawmosnaretuc/swen/moc.aideptfos.swen

Read:2374 | Comments:0 | Tags:Virus alerts

“cuteRansomware Uses Google Docs as C&C Server”0 Comments

Submit A Comment

Name:

Email:

Blog :

Verification Code:

Announce

Share high-quality web security related articles with you:)

Tools

Tag Cloud