CVE-2022-38105

Executive Summary

CVE-2022-38105 is an unauthenticated information disclosure vulnerability in the configuration service of the Asus RT-AX82U router, specifically in the firmware build 3.0.0.4.386_49674-ge182230. The flaw resides in the cm_processREQ_NC opcode handler, which processes network requests and can be triggered remotely by a specially crafted packet, leading to the disclosure of sensitive device information. With a CVSS score of 7.5 and no known patch, affected routers remain exposed to remote attackers who can harvest configuration details without authentication. Enterprise networks using this consumer-grade device as a perimeter gateway face a heightened risk of reconnaissance and subsequent lateral movement.

Technical Analysis

The NVD description identifies the vulnerability as an information disclosure issue within the cm_processREQ_NC opcode of the router's configuration service. The term "opcode" indicates that the configuration service implements a proprietary binary protocol, likely over HTTP or a custom TCP/UDP port, where specific numeric operation codes dispatch to handler functions. The cm_ prefix suggests a "configuration manager" module responsible for processing device management commands.

The vulnerability class is a missing or insufficient authorization check combined with an information disclosure flaw. The handler processes the cm_processREQ_NC opcode without requiring authentication, and the response to a crafted request leaks sensitive data. This could include device settings, network topology details, WAN/LAN IP addresses, DNS server information, or Wi-Fi credentials, although the specific data elements are not enumerated in the public description.

The attack surface is the router's configuration service, which is exposed on the network-facing interface. Asus routers typically listen on port 80/443 for web management and may expose additional TCP ports for proprietary services. The fact that the attack is triggered by a "specially-crafted network packet" and not a standard HTTP request suggests the service may use a binary framing format, making manual exploitation less trivial but still feasible with protocol reverse engineering.

No public exploit code or PoC has been confirmed, and the vendor has not released a patched firmware. Insufficient technical detail is available to specify the exact request structure or the precise data leaked; the analysis is therefore limited to the vulnerability class and the mechanism described in the NVD entry.

Exploitation Scenarios

The attack chain for CVE-2022-38105 proceeds as follows, with steps inferred from the vulnerability class due to the absence of public exploit details:

1. Reconnaissance / Target Identification: The attacker identifies Asus RT-AX82U routers exposed to the internet. This is achievable via Shodan or Censys queries targeting the default web management interface title "ASUS Wireless Router" or the device model string. Alternatively, the attacker scans a target network's IP range for open ports commonly associated with Asus router management services (e.g., 80, 443, or proprietary ports). The attacker may also fingerprint the firmware version via the login page or HTTP headers to confirm build 3.0.0.4.386_49674-ge182230 is in use.

2. Triggering the Flaw: The attacker crafts a network packet that targets the configuration service and sets the opcode field to cm_processREQ_NC. Because the service fails to enforce authentication for this opcode, the request is processed without a valid session or login credentials. The attacker does not need to bypass a login page — they simply send the malformed or specially formatted request directly to the service endpoint, likely on the WAN interface if remote management is enabled, or on the LAN interface if the attacker is on the local network.

3. Payload / Execution Method: At the vulnerability-class level, the attack is a direct service request with a crafted opcode. The "payload" is the specific binary frame containing the cm_processREQ_NC operator. The server responds with a data structure containing sensitive configuration information. No command execution or memory corruption is involved — this is a pure data exposure issue.

4. Post-Exploitation Impact: The attacker obtains device configuration details. Depending on what is exposed, this could enable credential harvesting (if Wi-Fi or admin passwords are included), network mapping for follow-on attacks, or targeted phishing. In an enterprise context, if the router is used as a small-office gateway, the leaked WAN IP and DNS settings could facilitate a more precise attack on the upstream network, potentially leading to session hijacking or man-in-the-middle positioning. Given the lack of authentication on the vulnerability itself, the attacker does not require any prior foothold.

No public PoC is available; the attack chain is inferred from the vulnerability class and the NVD description.

Impact Assessment

The CVSS score of 7.5 reflects a high-severity issue with a network attack vector, low attack complexity, no privileges required, and no user interaction — meaning the vulnerability is trivially exploitable by any remote attacker who can reach the router's configuration service. The confidentiality impact is rated High, while integrity and availability are unaffected.

Business impact depends on deployment context. For a home user, the leak of Wi-Fi credentials or ISP login details enables unauthorized network usage and potential fraud. For an enterprise or SMB that uses the RT-AX82U as a site-to-site VPN endpoint or branch gateway, the leaked configuration could expose internal network ranges, VPN pre-shared keys, or DDNS credentials — enabling an attacker to pivot into the corporate network. The blast radius is exacerbated by the lack of a patch: all affected devices are permanently exposed until the vendor ships a fix or the device is replaced.

The EPSS score of 0.01082 (62.1st percentile) indicates a low but non-trivial probability of exploitation in the wild, consistent with the absence of public PoC and the niche device population.

Detection Guidance

Detection of exploitation attempts requires monitoring traffic to the router configuration service and observing anomalous requests that do not match normal administrative sessions.

Sigma Rule

title: Asus RT-AX82U cm_processREQ_NC Information Disclosure Attempt
id: 8f7c2d9e-4a51-4b6f-9d3c-2a1b0e5f6c7d
status: experimental
description: Detects network traffic targeting the Asus RT-AX82U configuration service with the cm_processREQ_NC opcode, indicating a potential information disclosure attempt.
logsource:
  category: network_connection
  product: firewall
detection:
  selection:
    dest_port:
      - 80
      - 443
      - 8080
    dest_ip: "10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16"
    bytes_sent: "> 200"
  condition: selection
level: high
falsepositives:
  - Legitimate router management traffic if the opcode is used for normal operations
tags:
  - attack.t1190
  - cve.2022.38105

YARA Rule

rule Asus_RT_AX82U_cm_processREQ_NC_exploit {
    meta:
        author = "ValterSec Threat Intel"
        date = "2025-04-08"
        description = "Detects binary payloads containing cm_processREQ_NC opcode patterns targeting Asus RT-AX82U"
        cve = "CVE-2022-38105"
    strings:
        $opcode = { 63 6d 5f 70 72 6f 63 65 73 73 52 45 51 5f 4e 43 } // cm_processREQ_NC ASCII
        $model_ref = "RT-AX82U" ascii
    condition:
        $opcode and #opcode > 0
}

Suricata IDS Rule

alert tcp any any -> $HOME_NET 80,443,8080 (msg:"ET EXPLOIT Asus RT-AX82U cm_processREQ_NC Information Disclosure Attempt"; flow:to_server,established; content:"cm_processREQ_NC"; nocase; sid:2025089; rev:1; metadata:cve CVE-2022-38105;)

Elastic Detection

sequence by source.ip
  [network where network.protocol == "http" and
   destination.port in (80, 443, 8080) and
   url.path : "*config*" or request.body : "*cm_processREQ_NC*"]
  [network where network.protocol == "http" and
   destination.port in (80, 443, 8080) and
   response.body : "*password*" or response.body : "*ssid*"]

Splunk SPL Query

index=firewall OR index=proxy
| where dest_port IN (80, 443, 8080)
| search "cm_processREQ_NC"
| stats count by src_ip, dest_ip, dest_port, _time
| sort - _time
| table _time, src_ip, dest_ip, dest_port, count

Wazuh OSSEC Rule

<rule id="100389" level="12">
  <decoded>cm_processREQ_NC</decoded>
  <description>Asus RT-AX82U cm_processREQ_NC opcode detected - potential CVE-2022-38105 exploitation</description>
  <group>network_exploit,cve_2022_38105,</group>
  <mitre>
    <id>T1190</id>
  </mitre>
</rule>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. As of the latest tracking, Asus has not released a firmware update addressing CVE-2022-38105. The affected build 3.0.0.4.386_49674-ge182230 remains vulnerable.

1. Immediate Mitigations:

   • Disable remote management (WAN-side access) on the router's administration panel if it is enabled. This restricts the attack surface to the LAN, reducing exposure from internet-based attackers.
   • Restrict access to the configuration service by IP allowlist via the router's firewall rules, permitting only trusted administrative IPs.
   • Monitor router logs and network traffic for anomalous requests to non-standard ports or the presence of the cm_processREQ_NC pattern.

2. Patch/Upgrade Steps:

   • Periodically check the Asus support site (https://www.asus.com/support/) for a new firmware release for the RT-AX82U.
   • If a patched firmware becomes available, download and apply it via the router's web interface under Administration > Firmware Upgrade.
   • As a stopgap, consider downgrading to an earlier firmware build if the current version is the only affected one; however, verify that the older build is not vulnerable to other known CVEs.

3. Long-Term Hardening:

   • Replace the RT-AX82U with a router that has an active security maintenance program and a track record of timely patches, especially if the device is used in a business context.
   • Segment the network: place routers and other network infrastructure on a dedicated management VLAN with strict egress controls.
   • Implement network-level intrusion detection (e.g., Suricata/Snort) on the perimeter to monitor for signatures of exploitation attempts against network devices.
   • Enforce a policy of quarterly firmware review for all network appliances, with documented vulnerability assessment before deployment.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2022-38105 — Official CVE record with description and CVSS metrics.
2. Asus Security Advisory: https://www.asus.com/support/ — Vendor support page for firmware updates; no dedicated advisory released at time of writing.
3. CISA KEV Catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog — CVE-2022-38105 not listed; no known exploitation in the wild.
4. Shodan Search Reference: https://www.shodan.io/search?query=http.title%3A%22ASUS+Wireless+Router%22 — Example query for identifying exposed Asus routers.
5. ValterSec Threat Intelligence Report Database: Internal reference for CVSS and EPSS scoring context.

Threat Actor Activity: No known threat actor campaigns have been publicly attributed to this CVE. The absence of CISA KEV listing and the lack of public PoC suggest opportunistic exploitation is unlikely, but the vulnerability remains a latent risk for devices reachable from the internet.