cbcvebase.
CVE-2023-39780
published 2023-09-11

CVE-2023-39780: On ASUS RT-AX55 3.0.0.4.386.51598 devices, authenticated attackers can perform OS command injection via the /start_apply.htm qos_bw_rulelist parameter. NOTE…

PriorityP187high8.8CVSS 3.1
AVNACLPRLUINSUCHIHAH
KEVITW
CISA Known Exploited Vulnerabilitydue 2025-06-23
Exploited in the wild
EPSS
33.64%
98.2th percentile
On ASUS RT-AX55 3.0.0.4.386.51598 devices, authenticated attackers can perform OS command injection via the /start_apply.htm qos_bw_rulelist parameter. NOTE: for the similar "token-generated module" issue, see CVE-2023-41345; for the similar "token-refresh module" issue, see CVE-2023-41346; for the similar "check token module" issue, see CVE-2023-41347; and for the similar "code-authentication module" issue, see CVE-2023-41348.

Affected

2 ranges
VendorProductVersion rangeFixed in
asusrt-ax55
asusrt-ax55_firmware

Detection & IOCsextracted from sources · hover to see the quote

ip101.99.91.151
ip101.99.94.173
ip79.141.163.179
ip111.90.146.237
portTCP/53282
otherssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAo41nBoVFfj4HlVMGV+YPsxMDrMlbdDZ...
url/start_apply.htm
  • Check ASUS routers for SSH listening on non-standard port TCP/53282, which is the backdoor port installed by the AyySSHush campaign exploiting CVE-2023-39780.
  • Inspect the router's authorized_keys file for unauthorized SSH public key entries beginning with 'ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAo41nBoVFfj4HlVMGV+YPsxMDrMlbdDZ'.
  • Monitor for HTTP POST requests targeting /start_apply.htm with the qos_bw_rulelist parameter, which is the injection vector for CVE-2023-39780.
  • Sift flagged just three HTTP POST requests — targeting ASUS router endpoints — for deeper inspection; even very low-volume POST traffic to ASUS router management endpoints should be investigated.
  • Detect presence of a self-signed TLS certificate with a 100-year lifetime on AiCloud services as an indicator of compromise in the WrtHug/AyySSHush campaign.
  • The backdoor is stored in NVRAM, so it persists across firmware upgrades and reboots; a firmware update alone will NOT remove the SSH backdoor if the router was previously compromised.
  • Attackers disable router logging and Trend Micro's AiProtection as part of the exploitation chain; absence of logs on a potentially compromised device should itself be treated as a suspicious indicator.
  • ·The attacker's SSH public key and port 53282 configuration are stored in NVRAM (non-volatile memory), not on disk, so they survive both reboots and firmware upgrades. A full factory reset followed by manual reconfiguration is required to remove the backdoor.
  • ·The initial authentication bypass techniques used in the exploitation chain have not been assigned CVEs, meaning CVE-based patch tracking alone is insufficient to confirm a device is protected.

CVSS provenance

nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vulncheck8.8HIGH
cisa8.8HIGH
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