cbcvebase.
CVE-2017-6549
published 2017-03-09

CVE-2017-6549: Session hijack vulnerability in httpd on ASUS RT-N56U, RT-N66U, RT-AC66U, RT-N66R, RT-AC66R, RT-AC68U, RT-AC68R, RT-N66W, RT-AC66W, RT-AC87R, RT-AC87U…

PriorityP274high8.8CVSS 3.0
AVNACLPRNUIRSUCHIHAH
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
7.55%
93.8th percentile
Session hijack vulnerability in httpd on ASUS RT-N56U, RT-N66U, RT-AC66U, RT-N66R, RT-AC66R, RT-AC68U, RT-AC68R, RT-N66W, RT-AC66W, RT-AC87R, RT-AC87U, RT-AC51U, RT-AC68P, RT-N11P, RT-N12+, RT-N12E B1, RT-AC3200, RT-AC53U, RT-AC1750, RT-AC1900P, RT-N300, and RT-AC750 routers with firmware before 3.0.0.4.380.7378; RT-AC68W routers with firmware before 3.0.0.4.380.7266; and RT-N600, RT-N12+ B1, RT-N11P B1, RT-N12VP B1, RT-N12E C1, RT-N300 B1, and RT-N12+ Pro routers with firmware before 3.0.0.4.380.9488; and Asuswrt-Merlin firmware before 380.65_2 allows remote attackers to steal any active admin session by sending cgi_logout and asusrouter-Windows-IFTTT-1.0 in certain HTTP headers.

Affected

1 ranges
VendorProductVersion rangeFixed in
asusrt-ac53_firmware

Detection & IOCsextracted from sources · hover to see the quote

cookieasus_token=cgi_logout
uaasusrouter-Windows-IFTTT-1.0
urlhttp://192.168.1.1/syslog.txt
urlhttp://192.168.1.1/apply.cgi1
commandcurl -H 'User-Agent: asusrouter-Windows-IFTTT-1.0' -H 'Cookie: asus_token=cgi_logout' http://192.168.1.1/syslog.txt
commandcurl -H 'User-Agent: asusrouter-Windows-IFTTT-1.0' -H 'Cookie: asus_token=cgi_logout' http://192.168.1.1/apply.cgi1 -d 'action_mode=reboot&action_script=&action_wait=70'
  • Detect exploit attempts by matching HTTP requests containing both the Cookie header value 'asus_token=cgi_logout' and the User-Agent string 'asusrouter-Windows-IFTTT-1.0' simultaneously — this exact combination triggers the session hijack bypass in ASUS httpd.
  • Monitor HTTP requests to ASUS router admin endpoints (e.g., /syslog.txt, /apply.cgi) for the User-Agent 'asusrouter-Windows-IFTTT-1.0' combined with Cookie 'asus_token=cgi_logout'; this is the exact PoC pattern for unauthenticated admin access.
  • The vulnerable code path is in the 'search_token_in_list' function in httpd: when the token equals 'cgi_logout' and the User-Agent starts with 'asusrouter', authentication is bypassed. Look for process-level anomalies in httpd on affected ASUS firmware versions.
  • Alert on POST requests to /apply.cgi with body parameter 'action_mode=reboot' originating from a session using the exploit User-Agent and cookie, indicating attempted router reboot or command execution.
  • ·The exploit only succeeds if at least one legitimate admin session is currently active on the router; there must be an existing entry in the token list for the bypass logic to match.
  • ·Multiple firmware branches are affected with different fix thresholds: mainstream models require firmware >= 3.0.0.4.380.7378, RT-AC68W requires >= 3.0.0.4.380.7266, and a third group (RT-N600, RT-N12+ B1, etc.) requires >= 3.0.0.4.380.9488. Asuswrt-Merlin requires >= 380.65_2.

CVSS provenance

nvdv3.08.8HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv2.09.3CRITICALAV:N/AC:M/Au:N/C:C/I:C/A:C
vulncheck8.8HIGH
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