Dubbed “Darlloz”, its targets are not just traditional computers, but also Internet-enabled devices such as home routers, set-top boxes, security cameras, and even industrial control systems. The worm inserts itself into target devices by exploiting a PHP vulnerability that has been patched as far back as May 2012.
“Upon execution, the worm generates IP addresses randomly, accesses a specific path on the machine with well-known ID and passwords, and sends HTTP POST requests, which exploit the vulnerability. If the target is unpatched, it downloads the worm from a malicious server and starts searching for its next target,” explains researcher Kaoru Hayashi. “Currently, the worm seems to infect only Intel x86 systems, because the downloaded URL in the exploit code is hard-coded to the ELF binary for Intel architectures.”
But, the researchers have also discovered that the attacker has also created variants of the worm aimed at other architectures such as ARM, PPC, MIPS and MIPSEL - usually used in the aforementioned Internet-enabled devices. He or she apparently created the worm based on proof-of-concept code published late last month.
To prevent spreading the worm, users should update their systems and devices, but many won’t even know they use them, and if they do, there’s always the distinct possibility that an update has not been provided by the vendors due to a variety of reasons.
They should also consider updating their security software and making their devices’ passwords stronger, the researchers say, and block incoming HTTP POST requests to several specific paths at the gateway or on each device.
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