CVE-2021-27102Accellion FTA OS Command Injection Vulnerability
CVE-2021-27102 is a OS command injection in Accellion FTA, rated high (7.8 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
Input reaches an operating-system command line, letting an attacker run their own commands on the host.
How it is reached
An attacker can exploit it by someone who can already run code or sign in on the machine, with an ordinary user 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 run commands or code with the privileges of the affected service.
Is it being exploited?
CISA added it to the Known Exploited Vulnerabilities catalog on 2021-11-03: it is being exploited in the wild. CISA links it to ransomware campaigns. EPSS estimates a 3.7% chance of exploitation activity in the next 30 days, higher than 90% of scored CVEs.
What to do
- Treat it as urgent: it is on CISA's KEV list. CISA's deadline for US federal agencies: 2021-11-17.
- No fixed version is listed yet. Find every place Accellion FTA runs, watch the references for a fix, and plan a replacement if it is no longer supported.
- Limit who can run code or sign in on the hosts that run it.
- Check exposed instances for signs of compromise, not only for the version.
Description from NVD
Accellion FTA 9_12_411 and earlier is affected by OS command execution via a local web service call. The fixed version is FTA_9_12_416 and later.
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
- Application servers and the hosts they run on. The flaw sits between untrusted input and code or command execution.
- Template engines. The flaw sits between untrusted input and code or command execution.
Trust boundaries in play
- Host boundary. The attacker needs a foothold on the machine first; the flaw turns a small foothold into a bigger one.
- Between untrusted input and code or command execution. An attacker who crosses it can run commands or code with the privileges of the affected service.
Questions to answer about your own systems
- Where does Accellion FTA run in your systems, and at which version?
- Which of those hosts also run code or users you do not fully trust?
- What can it reach once compromised: which data stores, secrets and services?
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.