BlackBerry Cylance Threat Researchers recently discovered obfuscated malicious code embedded within WAV audio files. Each WAV file was coupled with a loader component for decoding and executing malicious content secretly woven throughout the file’s audio data. When played, some of the WAV files produced music that had no discernible quality issues or glitches. Others simply generated static (white noise).
The WAV file loaders can be grouped into the following three categories.
Loaders that employ Least Significant Bit (LSB) steganography to decode and execute a PE file.
Loaders that employ a rand()-based decoding algorithm to decode and execute a PE file.
Loaders that employ rand()-based decoding algorithm to decode and execute shellcode.
Each approach allows the attacker to execute code from an otherwise benign file format. These techniques demonstrate that executable content could theoretically be hidden within any file type, provided the attacker does not corrupt the structure and processing of the container format. Adopting this strategy introduces an additional layer of obfuscation because the underlying code is only revealed in memory, making detection more challenging.
Exposure of sensitive information