This record tracks a ransomware attack claimed by the
blacklock group against
MCM Construction. It collects the publicly disclosed attack details — sector, location and
timeline — as published on the operator's leak site and indexed by Breach House.
Window Zero
EXPOSURE GAP
Window Zero is the time the breach stayed in the open before
anyone said so — the gap between when the attack was first discovered
on the operator's leak site (t1) and when it was publicly disclosed (t2).
The wider this window, the longer victims, staff and customers were exposed with no warning.
-38days
t1 · Published
t2 · Disclosed
Business Category
Construction / Real Estate
Disclosed / Notified
Apr 23, 2025
Attack Summary
Commercial & Residential Construction
California, United States
<25 Employees
MCM Construction is a leading bridge construction company in the USA, known for building over 1000 critical structures across the West.
Revenue $26.1 Million
Leak Screenshots
SAMPLE
Proof-of-breach screenshots the operator posted from the stolen data. Previews are
redacted and locked — the originals are available on HaveIBeenRansom.
Dark Web Exposure
Findings for mcmconstructioninc.com
— indexed by HaveIBeenRansom.
0
found in Infostealer logs
281+
found in Traditional breaches
7+
found in Ransomware leaks
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B F R e p o V 3 F i l e s · breach
••• emails
LinkedIn.com.txt
Database World ROC · breach
••• emails
USA_Customers_04.2021_(153.986.518) @dbworldcloud.part01.rar
DBs Backup · breach
••• emails
+ 17 more leak sources locked
Leak volumes are locked
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Legal Disclaimer:
This ransomware victim record reflects information published on the operator's leak site.
Breach.house does not acquire, download, host, access or redistribute unlawfully obtained data. It indexes only publicly visible information posted by ransomware, breach and infostealer operators and open web sources, without accessing the underlying stolen content. The service supports public awareness, legitimate research and cyber-resilience.