The fetch API implementation in Mozilla Firefox before 41.0.2 does not restrict access to the HTTP response body in certain situations where user credentials are supplied but the CORS cross-origin request algorithm is improperly followed, which allows remote attackers to bypass the Same Origin Policy via a crafted web site.

The version of Mozilla Firefox is prior to 42.0 and is affected by multiple vulnerabilities : 

 - Multiple flaws in the browser engine allow remote attackers to corrupt memory and potentially execute arbitrary code. (CVE-2015-4513, CVE-2015-4514)
 - A flaw exists that is triggered when handling type 3 messages as part of the NTLM authentication exchange. This may allow an attacker to disclose system hostname and windows domain information. (CVE-2015-4515)
 - A flaw exists related to the whitelist used by Reader View to disable script for rendered pages being too permissive. This may allow an attacker to bypass CSP protections and in turn potentially conduct XSS attacks. (CVE-2015-4518)
 - An unspecified use-after-poison flaw exists in Mozilla Network Security Services (NSS) in the 'sec_asn1d_parse_leaf()' function that may allow an attacker to execute arbitrary code. (CVE-2015-7181)
 - An overflow condition exists in Mozilla Network Security Services (NSS) in the ASN.1 decoder. The issue is triggered as user-supplied input is not properly validated when handling an OCTET STRING. This may allow an attacker to cause a heap-based buffer overflow, resulting in a denial of service or potentially allowing the execution of arbitrary code. (CVE-2015-7182)
 - An integer overflow condition exists in Netscape Portable Runtime (NSPR) in the PL_ARENA_ALLOCATE macro that is triggered as user-supplied input is not properly validated during memory allocation. This may allow an attacker to corrupt memory, crashing an application linked against the library or potentially allowing the execution of arbitrary code. (CVE-2015-7183)
 - A flaw exists in the 'fetch()' API that is due it failing to properly implement the Cross-Origin Resource Sharing (CORS) feature. This may allow an attacker to potentially gain unauthorized access to cross-origin information. (CVE-2015-7184)- A flaw exists that is due to the program failing to enforce settings when disabling scripts in the Add-on SDK panel. By defining a panel with "script: false", all script execution is designed to be disabled. With a crafted web site, an attacker may be able to bypass this restriction, facilitating scripting attacks. (CVE-2015-7187)
 - A flaw exists in 'netwerk/base/nsStandardURL.cpp' that is triggered during the handling of trailing whitespaces in the IP address hostname. This may allow an attacker to bypass the same-origin policy. (CVE-2015-7188)
 - A race condition exists in the 'JPEGEncoder()' function. The issue is triggered as user-supplied input is not properly validated when handling canvas elements. This may allow an attacker to cause a heap-based buffer overflow and potentially execute arbitrary code. (CVE-2015-7189)
 - A flaw exists (Firefox for OS X only) in the 'ConvertToNSArray()' function in 'accessible/mac/mozAccessible.mm.' The issue is triggered when an accessibility tool requests the index of a table row via the 'NSAccessibilityIndexAttribute' value. This may allow an attacker to potentially execute arbitrary code. (CVE-2015-7192)
 - A flaw exists that is triggered during the handling of content-type headers for multiple media types returned from a server. This may allow an attacker to bypass cross-origin resource sharing (CORS) and perform simple request instead of a 'preflight' request. (CVE-2015-7193)
 - A flaw exists in the 'nsZipArchive::GetData()' function in 'modules/libjar/nsZipArchive.cpp' that is triggered as user-supplied input is not properly validated when handling ZIP archives. This may allow an attacker to corrupt memory and potentially execute arbitrary code. (CVE-2015-7194)
 - A flaw exists that is triggered during the parsing of escaped characters in the hostname of location headers. This may allow an attacker to gain access to arbitrary site-specific token information. (CVE-2015-7195)
 - A flaw exists in the '_releaseobject()' function in 'dom/plugins/base/nsNPAPIPlugin.cpp' that is triggered when JavaScript wrappers become deallocated during use. This may allow an attacker to corrupt memory and potentially execute arbitrary code. (CVE-2015-7196)
 - A flaw exists in the 'WebSocketImpl::Init()' function in 'dom/base/WebSocket.cpp' that is triggered when determining the origin of the entry settings object for workers. This may allow an attacker to bypass the mixed content WebSocket policy. (CVE-2015-7197)
 - An overflow condition exists in the 'WebGLTexture::EnsureInitializedImageData()' function in 'dom/canvas/WebGLTexture.cpp.' The issue is triggered as user-supplied input is not properly validated. This may allow an attacker to cause a buffer overflow and potentially execute arbitrary code. (CVE-2015-7198)
 - A flaw exists in 'dom/svg/SVGPathSegListSMILType.cpp' related to missing return value checks for the 'AddWeightedPathSegLists()' function during SVG rendering. This may allow an attacker to corrupt memory and execute arbitrary code. (CVE-2015-7199)
 - A flaw exists that is due to missing status checks in CryptoKey related to OOM (Out-of-Memory) conditions. This may allow an attacker to make changes to crpytographic keys and potentially execute arbitrary code. (CVE-2015-7200)

MozillaFirefox was updated to version 41.0.2 to fix one security issue.

This security issue was fixed :

  - CVE-2015-7184: Cross-origin restriction bypass using     Fetch (bsc#950686).

These non-security issues were fixed :

  - Fix a startup crash related to Yandex toolbar and     Adblock Plus (bmo#1209124)

  - Fix potential hangs with Flash plugins (bmo#1185639)

  - Fix a regression in the bookmark creation (bmo#1206376)

  - Fix a startup crash with some Intel Media Accelerator     3150 graphic cards (bmo#1207665)

  - Fix a graphic crash, occurring occasionally on Facebook     (bmo#1178601)

The remote Ubuntu 14.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-2768-1 advisory.

    Abdulrahman Alqabandi and Ben Kelly discovered that the fetch() API did not correctly implement the Cross     Origin Resource Sharing (CORS) specification. If a user were tricked in to opening a specially crafted     website, an attacker could potentially exploit this to obtain sensitive information from other origins.
    (CVE-2015-7184)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Firefox Developers report :

Security researcher Abdulrahman Alqabandi reported that the fetch() API did not correctly implement the Cross-Origin Resource Sharing (CORS) specification, allowing a malicious page to access private data from other origins. Mozilla developer Ben Kelly independently reported the same issue.

The version of Firefox installed on the remote Windows host is prior to 41.0.2. It is, therefore, affected by a cross-origin restriction bypass vulnerability in the fetch() API due to an incorrect implementation of the Cross-Origin Resource Sharing (CORS) specification. A remote attacker can exploit this, via a malicious website, to access private data from other origins.

The version of Firefox installed on the remote Mac OS X host is prior to 41.0.2. It is, therefore, affected by a cross-origin restriction bypass vulnerability in the fetch() API due to an incorrect implementation of the Cross-Origin Resource Sharing (CORS) specification. A remote attacker can exploit this, via a malicious website, to access private data from other origins.

ID	Name	Product	Family	Type	Severity
9018	Mozilla Firefox < 42.0 Multiple Vulnerabilities	Nessus Network Monitor	Web Clients		critical
86595	openSUSE Security Update : MozillaFirefox (openSUSE-2015-678)	Nessus	SuSE Local Security Checks	Local	medium
86443	Ubuntu 14.04 LTS : Firefox vulnerability (USN-2768-1)	Nessus	Ubuntu Local Security Checks	Local	high
86432	FreeBSD : firefox -- Cross-origin restriction bypass using Fetch (79c68ef7-c8ae-4ade-91b4-4b8221b7c72a)	Nessus	FreeBSD Local Security Checks	Local	medium
86418	Firefox < 41.0.2 'fetch' API Cross-Origin Bypass	Nessus	Windows	Local	medium
86417	Firefox < 41.0.2 'fetch' API Cross-Origin Bypass (Mac OS X)	Nessus	MacOS X Local Security Checks	Local	medium

Detections

Analytics

CVE-2015-7184

high

Tenable Plugins

critical

medium

high

medium

medium

medium