cbcvebase.
CVE-2021-45608
published 2021-12-26

CVE-2021-45608: Certain D-Link, Edimax, NETGEAR, TP-Link, Tenda, and Western Digital devices are affected by an integer overflow by an unauthenticated attacker. Remote code…

PriorityP271critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
EPSS
2.51%
83.0th percentile
Certain D-Link, Edimax, NETGEAR, TP-Link, Tenda, and Western Digital devices are affected by an integer overflow by an unauthenticated attacker. Remote code execution from the WAN interface (TCP port 20005) cannot be ruled out; however, exploitability was judged to be of "rather significant complexity" but not "impossible." The overflow is in SoftwareBus_dispatchNormalEPMsgOut in the KCodes NetUSB kernel module. Affected NETGEAR devices are D7800 before 1.0.1.68, R6400v2 before 1.0.4.122, and R6700v3 before 1.0.4.122.

Affected

3 ranges
VendorProductVersion rangeFixed in
netgeard7800_firmware< 1.0.1.681.0.1.68
netgearr6400v2_firmware< 1.0.4.1221.0.4.122
netgearr6700v3_firmware< 1.0.4.1221.0.4.122

Detection & IOCsextracted from sources · hover to see the quote

port20005
filenameNetUSB.ko
command0x805f
  • Monitor for inbound TCP connections to port 20005 (NetUSB service) from WAN-side interfaces, especially on router/embedded Linux devices running the KCodes NetUSB kernel module.
  • Flag NetUSB TCP/20005 sessions where the attacker-supplied 4-byte size value is 0xffffffff or any value where (size + 0x11) overflows to a value <= 0x10, as this is the integer overflow exploitation primitive.
  • Exploitation results in a kmalloc-32 slab allocation followed by an out-of-bounds write; kernel heap anomaly detection on embedded Linux devices should watch for unexpected kmalloc-32 slab corruption patterns.
  • ·The vulnerability is only reachable from the WAN if no firewall rules block TCP port 20005; devices with WAN-side firewall rules restricting this port are not directly exploitable from the internet.
  • ·Exploitation complexity is rated high; a working public exploit did not exist at time of disclosure, but cannot be ruled out in the future.
  • ·No in-the-wild exploitation was observed at time of public disclosure.
  • ·Affected NETGEAR devices requiring firmware updates are D7800 before 1.0.1.68, R6400v2 before 1.0.4.122, and R6700v3 before 1.0.4.122; end-of-life models are unlikely to receive patches.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvdv2.07.5HIGHAV:N/AC:L/Au:N/C:P/I:P/A:P
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