Cleaned The Hack.
It Came Back Anyway?
That Is A Backdoor. We Find It.
If your site was hacked, you cleaned it up, and it got reinfected days or weeks later, a backdoor is almost always the reason. A backdoor is a hidden file, disguised as legitimate WordPress code, that lets an attacker regain access even after you have changed every password and removed the original malware.
CV Infotech finds backdoors by comparing your files against known-clean WordPress checksums, not by scanning for obvious red flags, which is exactly the method needed to catch a file deliberately disguised to look normal.
What A WordPress Backdoor Actually Is
A backdoor is malicious code, usually a single small file or a snippet inserted into an existing legitimate file, that gives an attacker a way back into a WordPress site independent of the normal login process. Unlike the original hack that got the attacker in, a backdoor is specifically built to survive a cleanup, which is why removing the visible malware without finding the backdoor almost always results in reinfection within days or weeks.
Backdoors are commonly disguised using file names that closely resemble real WordPress core files, sometimes differing by a single character, or hidden inside legitimate files like wp-load.php or a theme's functions.php where a casual read-through would not notice a few extra lines among hundreds of normal ones. Some backdoors do not create a new file at all, instead modifying an existing core file's hash just slightly enough to add hidden functionality while still appearing to function normally.
Francisco Escobar's WordPress infrastructure has been checked against known-clean file hashes on every scheduled maintenance visit for the full 14 years CV Infotech has managed it, which is precisely the discipline that prevents a backdoor from surviving undetected across visits. That same hash-comparison method is the first thing we run on any backdoor removal engagement, and it is a standing feature of our plans at wordpress-maintenance-service.
We Compare Hashes, Not Just File Names
A backdoor disguised with a normal-looking file name still fails a hash comparison against the genuine WordPress core file it is impersonating, which is the method we rely on rather than a visual scan.
We Check Why The Hack Keeps Returning
If you have already attempted a cleanup that did not hold, we treat that specifically as evidence of a backdoor rather than repeating the same removal approach that already failed once.
Scheduled Tasks Reviewed Too
Some backdoors work through a WordPress cron job that periodically re-adds malicious code, which a file-only scan will miss entirely if the cron entry itself is not checked.
Full Removal Verified By Retesting
After removal, we retest over several days where practical, since a genuinely removed backdoor should not resurface, and a false all-clear is worse than an honest delay.
How We Find And Remove A WordPress Backdoor
Core File Hash Comparison
Every WordPress core file is compared against known-clean checksums from the official repository, which reveals both disguised new files and subtly modified existing ones that a visual inspection would miss.
Suspicious Filename Pattern Review
We check for files with names deliberately similar to legitimate WordPress files, a common disguise technique that relies on a site owner or even another scanner not noticing a single altered character.
functions.php and wp-load.php Deep Review
These files are common hiding places for backdoor code inserted among legitimate lines, since both load on nearly every page request and are rarely read in full by a site owner.
Cron Job Audit
WordPress scheduled tasks are checked for any entry that re-adds malicious code or reinstalls a backdoor automatically, which explains many cases where a cleanup appeared successful but the infection returned days later.
Uploads Folder Execution Check
We verify that no executable script has been placed in directories that should only contain media files, a common technique for maintaining hidden access outside the main codebase.
Written Findings Report
You receive the exact file or files identified as backdoors, their location, and confirmation that both the backdoor and its original entry point have been addressed.
Why CV Infotech For Backdoor Removal
A backdoor is specifically what separates a cleanup that holds from one that does not, and it is also the most common reason a site owner tells us they already tried to fix this once and it came back. That experience is frustrating but not unusual, since most automated scanners and even many manual cleanups focus on the visible symptom, the redirect, the spam, the defacement, without checking whether a separate re-entry mechanism was left behind.
Finding a well-disguised backdoor requires comparing against a genuine known-clean baseline rather than looking for anything that seems obviously wrong, since the entire purpose of a backdoor is to not seem obviously wrong. This is a slower, more methodical process than a quick scan, and it is the reason our removals tend to actually hold rather than needing to be repeated.
This service is not the right choice if:
- Your previous cleanup was performed by a security professional who already confirmed no backdoor was present
- You have not yet had any hack or reinfection and are asking purely out of general caution, see /wordpress-security/
- Your hosting provider's managed plan already includes backdoor scanning as part of their service
- You need a full site rebuild rather than a targeted cleanup, see /wordpress-development-company/
We will confirm which of these applies during the triage call before billing anything.
USA
Compliance: CCPA · Hosting: AWS us-east-1 · Support hours: EST (UTC-5)
Site and file access during the investigation is handled in compliance with CCPA, processed on AWS us-east-1 infrastructure, with updates communicated during EST business hours.
Full detailUK
Compliance: UK GDPR · Hosting: AWS eu-west-2 London · Support hours: GMT (UTC+0)
UK GDPR governs how any customer or account data encountered during the file review is handled. John Gowland's real estate platform in the UK is checked against the same hash-comparison standard applied to every backdoor engagement, supported on GMT hours.
Full detailAustralia
Compliance: Privacy Act 1988 · Hosting: AWS ap-southeast-2 Sydney · Support hours: AEST (UTC+10)
Privacy Act 1988 obligations are factored into how Australian client data is handled during the investigation. Laura Maher's ongoing WordPress work with us from Australia runs on this same AEST-aligned support model.
Full detailCommon Backdoor Hiding Spots, Ranked By Frequency
Where we actually find backdoors, most common first.
| # | Item | Why It Matters |
|---|---|---|
| 1 | Disguised file in wp-content/uploads | Uploads folders are rarely audited for executable scripts, common and effective hiding spot |
| 2 | Inserted lines in functions.php of the active theme | Loads on every page request, easy to overlook among legitimate theme code |
| 3 | Modified wp-load.php or wp-settings.php | Core files that load early, giving a backdoor broad access if compromised |
| 4 | A fake plugin disguised as a caching or SEO tool | Appears legitimate in the plugin list, easy to overlook during a quick review |
| 5 | mu-plugins directory | Loads automatically without appearing in the standard plugin list at all |
| 6 | Cron job re-adding a removed file | Explains reinfection days after an apparently successful cleanup |
| 7 | Hidden admin account created via direct database insert | Bypasses the normal user creation process and admin activity logs entirely |
| 8 | .htaccess-based backdoor allowing specific IP access | Grants an attacker persistent access that does not require any WordPress-level authentication at all |
We Use Hash Comparison, Not Guesswork
Files are checked against genuine known-clean WordPress checksums, the only reliable way to catch a deliberately disguised backdoor.
512 Verified 5.0 Reviews
512 reviews on Freelancer.com with a 5.0 rating, from real client engagements.
We Investigate Why A Previous Cleanup Failed
If this is a repeat infection, we treat that specifically as backdoor evidence rather than repeating an approach that already did not hold.
Francisco Escobar, 14 Years, Zero Breaches
Client since 2012. Hash-comparison checks have run on his infrastructure for the full 14 years without a confirmed breach.
How Backdoor Removal Works
If a previous cleanup was attempted, we review what was done and treat the recurrence as active backdoor evidence.
Every core, plugin, and theme file is compared against known-clean checksums to identify disguised or modified files.
Scheduled tasks and hidden admin accounts created via direct database insertion are checked specifically.
Every identified backdoor is removed, along with the original entry point that allowed installation in the first place.
We retest over the following days where practical, since a genuinely removed backdoor should not resurface.
You receive the exact backdoor location, the entry point, and confirmation that both have been addressed.
Frequently Asked Questions
Hack Keeps Coming Back? That Is A Backdoor. We Find It And Close It For Good.
$30/hr. Hash comparison scan, extended verification, written report.
Start Backdoor Removal at $30/hr