What is CVE-2016-9553?A high-severity flaw in Web Appliance, explained.
CVE-2016-9553 is a high-severity flaw (CVSS 7.2) in Web Appliance from Sophos, published on 28 January 2017. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 20%. If you run an affected version, plan in the vendor’s fix.
Published 28 January 2017. Record last updated 20 April 2025. We keep this page's data up to date.
What is CVE-2016-9553? In plain terms.
It can be attacked from anywhere on the internet with an administrator account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.
The Sophos Web Appliance (version 4.2.1.3) is vulnerable to two Remote Command Injection vulnerabilities affecting its web administrative interface. These vulnerabilities occur in the MgrReport.php (/controllers/MgrReport.php) component responsible for blocking and unblocking IP addresses from accessing the device. The device doesn't properly escape the information passed in the variables 'unblockip' and 'blockip' before calling the shell_exec() function which allows for system commands to be injected into the device. The code erroneously suggests that the information handled is protected by utilizing the variable name 'escapedips' - however this was not the case. The Sophos ID is NSWA-1258.
What kind of flaw is it?
- CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
How an attack on it works
Read straight from its severity rating, translated out of the shorthand.
- Where an attacker can beAnywhere on the internet
- How hard it is to pull offEasy: no special conditions
- Login needed firstAn administrator account
- Does someone have to clickNo, nobody has to do anything
- What an attacker getsCan read data, change data and take it offline
Severity vector: CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Is CVE-2016-9553 being exploited? Not that we know of.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 20%. That can change at any time, which is why we keep watching.
Timeline
- Published
- Record last updated
- Exploit likelihood jumped
CVE-2016-9553 scores 53. Action: Plan remediation.
We keep the score of every published flaw up to date as the evidence changes. Four things go into the score, and evidence that criminals are actually using it counts most. In order:
- Evidence it is being exploitedBiggest factor
- How severe it isStrong factor
- How widely exposed it isSmaller factor
- Threat activity around itSmaller factor
85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score.
When CVE-2016-9553 matches software you track, it lands in your list with its score and the reasons behind it.
See your own ranked list →Who is affected by CVE-2016-9553? One product.
The published record lists 1 product from 1 vendor. If you run one of these, check your version, then go to the fix below.
- Application
Web Appliance
by Sophos
Affected versions4.2.1.3
How do I fix CVE-2016-9553? Four steps.
- Check whether you run itCompare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list.
- Apply the vendor’s fixInstall the latest update from the vendor. The references list where the vendor has published details.
- If you can’t patch todayFollow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in.
- Keep an eye on itTrack the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood.
Does CVE-2016-9553 affect you? We'll keep checking.
Looking flaws up one at a time doesn't scale. Tell us what you run once, and we tell you which flaws matter to you, in what order, and keep watching for new ones.
- Tell us what you runPick your software from a list, or let us work it out from your website.
- We match it to every flawOver 400,000 published flaws, checked against your list.
- Ranked by real-world riskA 0 to 100 score, led by evidence criminals are using it.
- Told as soon as we knowAn alert by email, in the app or by webhook to your own tools.
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1 new flaw affects software Acme tracks
The Sophos Web Appliance (version 4.2.1.3) is vulnerable to two Remote Command Injection vulnerabilities affecting its web administrative interface. These vu...
- Matched to
- Web Appliance on Acme's software list
- What to do
- Plan in the vendor’s update
Sent to the alert recipients Acme chose. Also in the app and to Acme's webhook.
CVE-2016-9553 is a high-severity flaw in Web Appliance from Sophos, published on 28 January 2017. It can be attacked from anywhere on the internet with an administrator account, and nobody has to click anything. If it works, the attacker can read data, change data and take it offline.
It scores 7.2 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2016-9553 is 53 out of 100, which is Medium. Its action is "Plan remediation". Not confirmed as exploited yet, but serious or likely enough that it should not wait for a quiet month.
It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 20%. That can change at any time, which is why we keep watching.
For Web Appliance from Sophos: 4.2.1.3.
Install the update the vendor names in its advisory. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet.