Cloudanix VulnDB

CVE-2017-8548

High · 7.5

CVSS

7.5

EPSS

67.6%

Published

Jun 15, 2017

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Attend

A flaw in how certain web server software handles memory can let attackers steal information or take over systems if users visit malicious pages.

Exploit Available Chainable
Exploitation
Requires User Interaction
Attacker needs
User Interaction
Complexity
High
Impact
Full Compromise
Component
Application
Class
Memory Corruption
Remediation
Patch
Effort
Medium
Patch risk
Low

What it actually does

Memory corruption in the scripting engine allows an attacker to read or write arbitrary memory locations through improper object handling, enabling information disclosure that can be leveraged for further compromise.

Why it matters to the business

Successful exploitation can result in theft of sensitive data and full system takeover on affected h2o deployments across Debian and Ubuntu systems; the high EPSS score and public exploit availability increase the likelihood of attacks, though it is not known to be used in ransomware.

How an attack unfolds

An attacker crafts a malicious webpage or HTTP response that triggers the scripting engine memory corruption when rendered or processed by the vulnerable h2o server or browser component, allowing arbitrary memory reads to leak addresses and bypass protections for further code execution.

How to fix it

Upgrade h2o to the fixed versions 2.2.4+dfsg-1 on Debian 10-13 or 2.2.4+dfsg-1build1 on Ubuntu 18.04 LTS; apply Microsoft security updates for Edge on Windows 10 and Server 2016 if applicable.

How to confirm the fix worked

Verify package versions match or exceed the listed fixed releases using apt or dpkg; confirm absence of the vulnerable memory handling code paths via source review or updated binary hashes.

Typical attack path

  1. Identify reachable h2o instances or Edge browsers on supported Windows versions
  2. Deliver crafted content via web request or page that exercises the memory corruption primitive
  3. Use disclosed memory information to defeat ASLR and execute arbitrary code or exfiltrate data

How to detect it

Review web server access logs for unusual scripting or object requests that precede crashes; inspect process memory dumps or crash reports on h2o instances for corruption signatures; correlate with outbound data exfiltration attempts.

What your security team should do

  • Prioritize upgrading all listed h2o packages to the specified fixed versions immediately given public exploit availability
  • Scan environments for any remaining vulnerable h2o instances on Debian/Ubuntu and schedule emergency patches
  • Monitor EPSS trends and block known malicious web content patterns targeting scripting engines

The record

Microsoft Edge in Microsoft Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allows an attacker to obtain information to further compromise the user's system when Microsoft Edge improperly handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8499, CVE-2017-8520, CVE-2017-8521, and CVE-2017-8549.

Affected packages

Ecosystem Package Introduced Fixed

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