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Zscaler Security Advisories

Security Advisory - April 10, 2018

Zscaler protects against 4 new vulnerabilities for Adobe Flash Player.

Zscaler, working with Microsoft through their MAPP program, has proactively deployed protections for the following 4 vulnerabilities included in the April 2018 Adobe security bulletins. Zscaler will continue to monitor exploits associated with all vulnerabilities in the April release and deploy additional protections as necessary.

APSB18-08 – Security updates available for Adobe Flash Player.

Adobe has released security updates for Adobe Flash Player for Windows, Macintosh, Linux and Chrome OS. These updates address critical vulnerabilities in Adobe Flash Player 29.0.0.113 and earlier versions. Successful exploitation could lead to arbitrary code execution in the context of the current user.

Severity: Critical
Affected Software

  • Adobe Flash Player Desktop Runtime 29.0.0.113 and earlier versions for Windows, Macintosh and Linux
  • Adobe Flash Player for Google Chrome 29.0.0.113 and earlier versions for Windows, Macintosh, Linux and Chrome OS 
  • Adobe Flash Player for Microsoft Edge and Internet Explorer 11 29.0.0.113 and earlier versions for Windows 10 and 8.1

CVE-2018-4934 – Adobe Flash Player Out-of-bounds Read Vulnerability

This vulnerability occurs as a result of computation that reads data that is past the end of the target buffer; the computation is part of the Flash’s image parsing. A malformed PNG (Portable Network Graphics) input leads to flawed computation that involves pointer offset arithmetic which does not adequately account for the buffer boundaries. The use of an invalid (out-of-range) pointer offset during access of internal data structure fields causes the vulnerability. A successful attack can lead to sensitive data exposure.

CVE-2018-4935 – Adobe Flash Player Out of Bounds Write Vulnerability

The vulnerability is caused by the computation that writes data past the end of the intended buffer; the computation is part of the graphics rendering. A crafted SWF code input triggers the flawed computation where pointer arithmetic is not appropriately checked against boundary conditions, which leads to memory write operation through the pointer that points to an invalid memory location. The vulnerability is a result of out of range pointer offset that is used to access sub-elements of an internal data structure representing a solid slab graphics element. An attacker can potentially leverage the vulnerability to corrupt sensitive data or execute arbitrary code.

CVE-2018-4936 – Adobe Flash Player Heap Overflow Vulnerability

This vulnerability is an instance of a heap overflow vulnerability when processing sound even data. Specifically, the vulnerability is triggered by a crafted audio coding specification within the SWF file which causes an out of bounds memory access, due to improper bounds checking when manipulating a pointer to a heap allocated buffer. Attackers can exploit the vulnerability by using the out of bounds access for unintended reads, writes or frees -- potentially leading to code corruption, control-flow hijack, or information leak attack.

CVE-2018-4937 – Adobe Flash Player Out of Bounds Write

The vulnerability is caused by the computation that writes data past the end of the intended buffer; the computation is part of the routine that applies a blur visual affect to display objects. A crafted SWF input triggers the flawed computation where pointer arithmetic is not appropriately checked against boundary conditions, which leads to memory write operation through the pointer that points to an invalid memory location. The vulnerability is a result of out of range pointer offset that is used to access sub-elements of an internal data structure. An attacker can potentially leverage the vulnerability to corrupt sensitive data or execute arbitrary code.