New KevDroid Android Backdoor Discovered

Security researchers have discovered a new Android Remote Access Trojan (RAT) that can steal a great deal of information from infected devices.

Dubbed KevDroid, the mobile threat can steal contacts, messages, and phone history, while also able to record phone calls, Talos reports. Two variants of the malware have been identified so far.

One of the variants exploits CVE-2015-3636 to gain root access, but both implement the same call recording capabilities, taken from an open-source project on GitHub.

Once it has infected a device, the first KevDroid variant can gather and siphon information such as installed applications, phone number, phone unique ID, location, stored contacts information, stored SMS, call logs, stored emails, and photos.

Large in size, the second variant of the malware was hosted at the same URL in February, and has been observed using SQLite databases to store data. It includes the same data gathering capabilities, along with camera recording, audio recording, web history stealing, file stealing, and the ability to gain root on the device.

An ELF file embedded in the APK attempts to exploit the CVE-2015-3636 vulnerability using code available on GitHub to obtain root permission. By gaining higher privileges, the malware can perform more in-depth actions, including stealing files from other applications.

“If an adversary were successful in obtaining some of the information KevDroid is capable of collecting, it could result in a multitude of issues for the victim. The social aspect of a mobile device results in a large amount of data residing on the device. This can be sensitive data, such as photographs, passwords, banking information or social engineering,” Talos notes.

Attackers could also blackmail victims using images or information deemed secret, could steal credentials and multi-factor tokens (SMS MFA), and could also engage in banking/financial fraud using their access to privileged information. Should the infected device be used in corporate environments, a KevDroid attack could lead to cyber espionage, Talos says.

While analyzing the threat, the security researchers also discovered a Windows-targeting RAT hosted on the same C&C server. They called the malware PubNubRAT, because of it uses the PubNub global data stream network (DSN) as a C&C and leverages PubNub API to send orders to the compromised systems.

“Using legitimate services is always challenging for defenders. It’s hard to identify malicious communications hidden in legitimate network flows (especially if the requests use encryption via HTTPS),” Talos notes.

A RTF file attempting to exploit the CVE-2017-11882 vulnerability in Office using an embedded Microsoft Equation object is used for infection. The document is written in Korean and contains information on Bitcoin and China.

Once it has infected a system, the malware can steal files, download files, execute commands, kill processes, and take screenshots.

According to Talos, they started the investigation into these malware families because of a possible link to Group 123, but the evidence they discovered was too weak to identify a clear connection with the group.

“We do not have a strong link between the two malware samples and Group 123. The TTP overlaps are tenuous — using public cloud infrastructure as a C2 server is something other malware has used before as a technique, not just Group 123. Additionally, the C2 server is hosted in Korea, and this malware has been known to target Korean users. However, this information cannot lead us to a strong link,” Talos concludes.

Related: 3 Million New Android Malware Samples Discovered in 2017

Related: Android Malware Steals Data from Social Media Apps

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Ionut Arghire is an international correspondent for SecurityWeek.

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