New Apache PHP XSS Bug Displays Modified HTTP Request Text to Users
A researcher has discovered a cross-site scripting vulnerability caused by mishandling of a PHP header in Apache version 2.x. Upgrade PHP and review privileges for applications and services using it.
Antecedentes
Researcher Prashanth Varma posted PHP Bug #76582 for Apache version 2.x that details a cross-site scripting (XSS) bug which could allow an unauthenticated attacker to send a malicious POST request that echoes the embedded script in the body of the response. The Center for Internet Security (CIS) issued an advisory stating that PHP versions 7.2 (prior to 7.2.10), 7.1 (prior to 7.1.22), 7.0 (prior to 7.0.32) and 5.6 (prior to 5.6.38) are all vulnerable. This vulnerability has been assigned CVE-2018-17082.
Vulnerability details
Apache mishandles the “Transfer-Encoding: chunked” PHP header that normally sends data chunks to another host in a transfer request. When exploited, it displays text in an error window in the active browser session. The exploit requires a locally run script, but does not require user interaction or authentication to run. The attacker could include a malicious link in these error messages, opening the user up to further attack if clicked.
As with any XSS attack, unsanitized text could allow for arbitrary code execution beyond a simple error message. No instances of more sophisticated attacks have been seen at the time of this writing, but as time progresses, additional attacks could use this exploit as a vector.
Urgently required actions
Upgrade PHP to the latest version to ensure that assets have the latest security patches. We also recommend reviewing privileges and asset access of any apps or services that utilize PHP in order to understand what targets are at risk. And, as always, reinforce security awareness with users, so they know the risks of clicking on links in error messages. Clicking on new messages from trusted sites can be just as dangerous as clicking on messages from untrusted sources.
Identificación de los sistemas afectados
Tenable has released the following plugins to scan for this vulnerability. Please note that our plugins look for the affected PHP versions without regards to the target’s platform in order to err on the side of caution. Even though this vulnerability only appears to affect Apache at this time, we recommend upgrading PHP to the latest version, even for users using other platforms that utilize PHP, in order to ensure maximum risk reduction.
|
Plugin ID |
Description |
|
PHP 5.6.x < 5.6.38 Transfer-Encoding Parameter XSS Vulnerability |
|
|
PHP 7.0.x < 7.0.32 Transfer-Encoding Parameter XSS Vulnerability |
|
|
PHP 7.1.x < 7.1.22 Transfer-Encoding Parameter XSS Vulnerability |
|
|
PHP 7.2.x < 7.2.10 Transfer-Encoding Parameter XSS Vulnerability |
Obtenga más información
- Alert from the Center for Internet Security
Learn more about Tenable.io, the first Cyber Exposure platform for holistic management of your modern attack surface. Get a free 60-day trial of Tenable.io Vulnerability Management.
Artículos relacionados
Microsoft’s May 2024 Patch Tuesday Addresses 59 CVEs (CVE-2024-30051, CVE-2024-30040)
May 14, 2024Microsoft addresses 59 CVEs in its May 2024 Patch Tuesday release with one critical vulnerability and three zero-day vulnerabilities, two of which were exploited in the wild.
Tenable Cloud Security Study Reveals a Whopping 95% of Surveyed Organizations Suffered a Cloud-Related Breach Over an 18-Month Period
May 14, 2024The finding from the Tenable 2024 Cloud Security Outlook study is a clear sign of the need for proactive and robust cloud security. Read on to learn more about the study’s findings, including the main challenges cloud security teams face, their strategies for better protecting their cloud infrastructure and the tools they use to measure success.
Shifting the Paradigm: Why the Cyber Insurance Industry Should Focus on Preventive Security
May 13, 2024As claims and losses climb, it’s clear that preventive security should be prioritized more when designing a cyber insurance policy. Here’s why preventive security investments are cost effective and can lead to lower premiums.
