Description

CheckPoint reported about an Android malware 'FakeCalls' being distributed in South Korea again, impersonating phone calls for over 20 financial organizations and attempting to fool bankers into giving away their credit card details - the attack is called voice phishing or vishing. More than 2500 samples of the FakeCalls malware were found which showed malware developers had used a variety of combinations of impersonated financial organizations and implemented anti-analysis techniques for malware protection. The attack started with the distribution of FakeCalls malware via fake Korean banking applications on the victim's device through phishing, black SEO, or malvertizing. Then, the fake application offers the victim a loan with a low-interest rate. Once the victim is interested, the FakeCalls malware initiates a phone call that plays a recording from the bank's real customer support with instructions for getting the loan request approved. However, the FakeCalls malware can mask the phone number belonging to the attackers and instead display the impersonated bank's real number, to make a conversation realistic. If the victim is tricked into confirming their credit card details with the hope of getting a loan, then attackers will steal those credit card details. In addition to the vishing attack, FakeCalls can capture live audio and video streams from the infected device to collect additional information. Moreover, CheckPoint has highlighted three evasion techniques of FakeCalls malware. The first method of evasion, known as "multi-disk," involves changing the ZIP header data of the APK file and providing very high values for the EOCD record to trick automated analysis software. The second evasion method involves altering the AndroidManifest.xml file to obscure the starting marker, changing the structure of the strings and styles, and tampering with the offset of the last string to lead to incorrect interpretation. The third evasion technique involves adding numerous files inside nested directories in the APK's asset folder, resulting in file names and paths that are longer than 300 characters. tThismay cause issues with some security tools, making it difficult for them to find the infection.