Uninitialized Memory Exposure

Affecting openwhisk package, versions <3.3.1

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Overview

openwhisk JavaScript client library for the Apache OpenWhisk platform.

Affected versions of the package are vulnerable to Uninitialized Memory Exposure. If an openwhisk action uses a api_key option with a numeric value, then uninitialized memory might be exposed by the client.

Details

The Buffer class on Node.js is a mutable array of binary data, and can be initialized with a string, array or number.

const buf1 = new Buffer([1,2,3]);
// creates a buffer containing [01, 02, 03]
const buf2 = new Buffer('test');
// creates a buffer containing ASCII bytes [74, 65, 73, 74]
const buf3 = new Buffer(10);
// creates a buffer of length 10

Initializing a options.api_key option in such manner will cause uninitialized memory to be exposed.

Proof of concept by ChALkeR

var openwhisk = require('openwhisk');
var options = {apihost: '127.0.0.1:1433', api_key: 50};
var ow = openwhisk(options);
ow.actions.invoke({actionName: 'sample'}).then(result => console.log(result))

The first two variants simply create a binary representation of the value it received. The last one, however, pre-allocates a buffer of the specified size, making it a useful buffer, especially when reading data from a stream. When using the number constructor of Buffer, it will allocate the memory, but will not fill it with zeros. Instead, the allocated buffer will hold whatever was in memory at the time. If the buffer is not zeroed by using buf.fill(0), it may leak sensitive information like keys, source code, and system info.

You can read more about the insecure Buffer behavior on our blog.

Remediation

Upgrade openwhisk to version 3.3.1 or higher. Note This is vulnerable only for Node <=4

References

CVSS Score

6.2
medium severity
  • Attack Vector
    Local
  • Attack Complexity
    High
  • Privileges Required
    None
  • User Interaction
    None
  • Scope
    Unchanged
  • Confidentiality
    High
  • Integrity
    None
  • Availability
    None
CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:F/RL:O/RC:C
Credit
ChALkeR
CWE
CWE-201
Snyk ID
npm:openwhisk:20170302
Disclosed
18 Jul, 2017
Published
18 Jul, 2017