Palo Alto Networks Discovers Two Adobe Reader Privileged Java Script Zero-Days
Summary: Unit 42 at Palo Alto Networks discovered two zero-day vulnerabilities in Adobe Reader, CVE-2016-6957 and CVE-2016-6958, which Adobe patched on October 6, 2016. The flaws let attackers bypass restrictions on JavaScript API execution and on arbitrary script execution, and the write-up shows how a trusted function like ANSendApprovalToAuthorEnabled can be abused to call secured functions from privileged context. The researcher also found that app.launchURL could launch arbitrary Python scripts because Adobe's denylist of executable extensions omitted the '.pyw' extension.
Bottom line: Adobe's fix for the earlier CVE-2015-4451 blocked copying a reference to app.beginPriv, but the researcher bypassed it by copying the object's prototype - so the underlying bug stayed exploitable until the October 6 patch. A denylist that misses a single extension like '.pyw' is the difference between a blocked script and arbitrary code running on an endpoint.
Read the original at Unit 42 Palo Alto Networks ↗
- Topics
- Vulnerabilities & Patching
- Mentions
- CVE-2016-6957CVE-2016-6958
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