ASUS Routers Improper Authentication Vulnerability
ASUS · Routers
The administrator application on ASUS GT-AC2900 routers (before 3.0.0.4.386.42643) and Lyra Mini devices (before 3.0.0.4_384_46630) fails to properly authenticate requests, leaving the administrator interface exposed. An unauthenticated remote attacker can reach the administrator interface by sending crafted input, because an attacker-supplied value of '\0' matches the device's default value in some situations, and no user interaction or prior credentials are needed.
The administrator application on ASUS GT-AC2900 devices before 3.0.0.4.386.42643 and Lyra Mini before 3.0.0.4_384_46630 allows authentication bypass when processing remote input from an unauthenticated user, leading to unauthorized access to the administrator interface. This relates to handle_request in router/httpd/httpd.c and auth_check in web_hook.o. An attacker-supplied value of '\0' matches the device's default value of '\0' in some situations. Note: All versions of Lyra Mini and earlier which are unsupported (End-of-Life, EOL) are also affected by this vulnerability, Consumers can mitigate this vulnerability by disabling the remote access features from WAN.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 4/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 3 years after disclosure.
- Disclosedday 0
- First seen exploitedVulnCheck KEV evidence+3 yrs
- Added to CISA KEVEU database agrees+4 yrs
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
3 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 3PersistenceTA0003
Due to the router's administrative web-app having improper validation of session cookies, an unauthorized user can gain administrative access to the device management interface.
Privilege EscalationTA0004
Credential AccessTA0006
Detection
0 rules for this CVE · 75 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2021-32030 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
Exploitation for Privilege EscalationT106831 general rules
- Exploiting CVE-2019-1388criticalstable
- Audit CVE Eventcriticaltest
- HackTool - SysmonEOP Executioncriticaltest
- InstallerFileTakeOver LPE CVE-2021-41379 File Create Eventcriticaltest
- Possible Coin Miner CPU Priority Paramcriticaltest
- Potential CVE-2021-41379 Exploitation Attemptcriticaltest
- Potential SystemNightmare Exploitation Attemptcriticaltest
- Sudo Privilege Escalation CVE-2019-14287 - Builtincriticaltest
Account ManipulationT109835 general rules
- Password Change on Directory Service Restore Mode (DSRM) Accounthighstable
- Active Directory User Backdoorshightest
- Anomalous User Activityhightest
- AWS User Login Profile Was Modifiedhightest
- Bulk Deletion Changes To Privileged Account Permissionshightest
- Cisco Local Accountshightest
- Enabled User Right in AD to Control User Objectshightest
- ESXi Admin Permission Assigned To Account Via ESXCLIhightest
Network SniffingT10409 general rules
- Cisco Sniffingmediumtest
- Harvesting Of Wifi Credentials Via Netsh.EXEmediumtest
- New Network Trace Capture Started Via Netsh.EXEmediumtest
- PktMon.EXE Executionmediumtest
- Potential Network Sniffing Activity Using Network Toolsmediumtest
- Potential Packet Capture Activity Via Start-NetEventSession - ScriptBlockmediumtest
- Windows Pcap Driversmediumtest
- Network Sniffing - Linuxlowtest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX