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1. 32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW DRIVER
2. 32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW FULL
3. 32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW CODE
4. 32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW PC

“In the case of this kernel module, there’s a timeout of 16 seconds on the socket for receiving data, meaning the struct can be overflown up to 16 seconds after it is allocated. That means that the size supplied is only used as a maximum receive size and not a strict amount, like memcpy.”Įase of laying out the kernel heap for the overflow: “Many exploits require the use of heap holes in order to make sure that the vulnerable heap structure will be placed before the object that will be overwritten,” Van Amerongen added. “Underneath this function is the standard socket recv function. The amount of control over the overflow itself: The attacker controls the data being received over the socket, but is the size negotiable? “Since a size of 0xffffffff is not realistically exploitable on a 32-bit system, it’s necessary to take a look at how SoftwareBus_fillBuf actually works,” the researcher explained. “That means that the allocated object will always be in the kmalloc-32 slab of the kernel heap,” Van Amerongen noted. Size that can be allocated: The minimum size that can be allocated is 0x0, and the maximum is 0x10. There are a number of factors that play into the feasibility of exploiting this bug, according to the analysis: If(user_supplied_size + 0x11 Exploitability This integer overflow check should be performed before allocating memory with user supplied sizes, the firm noted: “From the previous example, the size 0xffffffff would be used here (not the overflown value) as the size sent to recv.”Īlong with its report, SentinelOne sent a suggested mitigation strategy, shown below. “Looking at the final call to SoftwareBus_fillBuf, the supplied size is used as a maximum value to read from the remote socket,” Van Amerongen said. Out-of-bounds writes taking place on the small allocated region.

32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW PC

The USB connection process starts with a handshake between the PC and router that initializes communication: a handshake that SentinelOne depicted in the graphic below. That discovery led to a “very helpful exploit” that helped to quickly verify the more recent vulnerability, Van Amerongen recounted. In 2015, there was another kernel stack buffer overflow in KCodes NetUSB. This isn’t the first time a worrisome NetUSB vulnerability has been discovered, either.

32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW FULL

The critical heap-overflow security vulnerability in the Linux kernel could have allowed local exploitation and RCE, leading to full system compromise. He does love to pop kernels: In November, Van Amerongen wrote up a bug (CVE-2021-43267) that he discovered in a Transparent Inter Process Communication (TIPC) message type that allows Linux nodes to send cryptographic keys to each other. “Provided there were no firewall rules in place to block it, that would mean it was listening on the WAN as well as the LAN. He came across the NetUSB kernel module while sifting through various paths through various binaries, where he saw something fishy: “As it turned out, this module was listening on TCP port 20005 on the IP 0.0.0.0,” Van Amerongen explained.

The device appeared in the 2019 Pwn2Own conference as well as being named as a target in Pwn2Own Austin 2021. ‘Who Doesn’t Love a Remote Kernel Bug?’Īs is his wont, Van Amerongen found the bug while poking around at a target of the Pwn2Own hacking contests: the aforementioned Netgear router, R6700v3. NetUSB is licensed to a slew of popular router vendors, including:įortunately, SentinelOne hasn’t yet spotted evidence of the flaw having been exploited in the wild.

32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW CODE

For remote users, it’s as if the USB devices are physically plugged into their local systems.Īccording to a Tuesday writeup from SentinelOne vulnerability researcher Max Van Amerongen, attackers could remotely exploit the vulnerability to execute code in the kernel via a pre-authentication buffer overflow security vulnerability, allowing device takeover.

32 BIT SYSTEM TIMEOUT INTEGER OVERFLOW DRIVER

This is made possible using the proprietary NetUSB protocol and a Linux kernel driver that launches a server, which makes the USB devices available via the network. The module enables remote devices to connect to routers over IP and access any USB devices (such as printers, speakers, webcams, flash drives and other peripherals) that are plugged into them. Millions of popular end-user routers are at risk of remote code execution (RCE) due to a high-severity flaw in the KCodes NetUSB kernel module.