cbcvebase.
CVE-2021-22017
published 2021-09-23

CVE-2021-22017: Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port…

PriorityP180medium5.3CVSS 3.1
AVNACLPRNUINSUCLINAN
KEVITWEXPLOIT
CISA Known Exploited Vulnerabilitydue 2022-01-24
Exploited in the wild
EPSS
49.18%
98.8th percentile
Rhttproxy as used in vCenter Server contains a vulnerability due to improper implementation of URI normalization. A malicious actor with network access to port 443 on vCenter Server may exploit this issue to bypass proxy leading to internal endpoints being accessed.

Affected

1 ranges
VendorProductVersion rangeFixed in
vmwarevcenter_server

Detection & IOCsextracted from sources · hover to see the quote

urlPOST /analytics/ceip/sdk/..;/..;/..;/analytics/ph/api/dataapp/agent?_c=vSphere.vapi.6_7&_i=9D36C850-1612-4EC4-B8DD-50BA239A25BB
urlPOST /analytics/ceip/sdk/..;/..;/..;/analytics/ph/api/dataapp/agent?action=collect&_c=vSphere.vapi.6_7&_i=9D36C850-1612-4EC4-B8DD-50BA239A25BB
path/analytics/ceip/sdk/..;/..;/..;/analytics/ph/api/dataapp/agent
otherX-Deployment-Secret: secret
  • Detect path traversal bypass attempts against vCenter rhttproxy using '..;/' sequences in the URI path targeting /analytics/ceip/sdk/
  • Successful exploitation of the first stage returns HTTP 201 with an empty body; the second stage returns HTTP 200 with response body containing 'BUILD', 'VERSION', and 'OSTYPE' strings indicating vCenter instance metadata disclosure.
  • Look for the custom header 'X-Deployment-Secret' with value 'secret' in POST requests to vCenter analytics endpoints as an indicator of exploitation attempts.
  • Monitor for POST requests to /analytics/ph/api/dataapp/agent with query parameters action=collect, _c=vSphere.vapi.6_7 as part of the two-stage exploit chain.
  • ·The exploit uses a randomized X-Plugin-Type header value (8-char random base string) per request, so this header value cannot be used as a static IOC for detection.
  • ·The vulnerability is exploitable without authentication from the network, requiring only access to port 443 on vCenter Server.

CVSS provenance

nvdv3.15.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
nvdv2.05.0MEDIUMAV:N/AC:L/Au:N/C:P/I:N/A:N
vulncheck5.3MEDIUM
cisa5.3MEDIUM
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