CVE-2017-9791Apache Struts 1 Improper Input Validation Vulnerability
CVE-2017-9791 is a improper input validation in Apache Struts 1, rated critical (9.8 on CVSS 3.1).
Why this priority: Exploited in the wild: listed in CISA's KEV catalog.
Published · Updated · NVD status: Analyzed
What it is
The software trusts input it should check, so crafted values reach code that assumes they are well formed.
How it is reached
An attacker can exploit it over the network, without an account, and nobody has to click anything.
What an attacker gains
A successful attack can read the data it protects, change data or behaviour and take it offline. In practice, this kind of flaw lets an attacker drive the component into behaviour its authors did not intend.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2022-02-10: it is being exploited in the wild. It can be exploited automatically, at scale. EPSS estimates a 99% chance of exploitation activity in the next 30 days, higher than 100% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2022-08-10.
- Apply the fix for Apache Struts 1: the patch and release notes are linked below.
- Until it is patched, keep it off the internet or behind a VPN, allowlist or authenticating proxy.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
The Struts 1 plugin in Apache Struts 2.1.x and 2.3.x might allow remote code execution via a malicious field value passed in a raw message to the ActionMessage.
What this means for your architecture.
A CVE names a product. Whether it matters depends on where that product sits in your systems: what reaches it, which trust boundary it guards and what it can reach once compromised. Veriom maps your components, their relationships and your trust boundaries from your code, cloud and delivery evidence, so you can see where a component like this sits. The radar itself does not look at your systems.
Components it touches
- Interfaces that accept external input. The flaw sits at the input boundary of the affected component.
Trust boundaries in play
- Internet-facing entry points. No account is needed. Any instance reachable from outside your perimeter, through a load balancer, gateway, VPN or exposed admin port, is in scope.
- At the input boundary of the affected component. An attacker who crosses it can drive the component into behaviour its authors did not intend.
Questions to answer about your own systems
- Where does Apache Struts 1 run in your systems, and at which version?
- Which of those instances can be reached from the internet or partner networks?
- What can it reach once compromised: which data stores, secrets and services?
Read more
Advisories
Sources
- CVE records and CVSS scores from the NVD CVE API. This product uses the NVD API but is not endorsed or certified by the NVD.
- Exploitation status from CISA’s Known Exploited Vulnerabilities catalog.
- Exploit likelihood from FIRST’s Exploit Prediction Scoring System (EPSS), refreshed daily.
- Explanations are written by Veriom from fixed templates over each record’s data, not by a person reviewing each CVE. Descriptions are quoted from the records as published.