This record tracks a ransomware attack claimed by the
sinobi group against
Lanmark Group. 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.
-59days
t1 · Published
t2 · Disclosed
Business Category
Communication / Marketing
Published
December 16, 2025
Disclosed / Notified
Oct 19, 2025
Attack Summary
Lanmark Group, Inc. is a full-service general contracting firm based in Brooklyn, NY, founded in 2005. The company specializes in handling complex construction projects for both public and private sector clients, demonstrating a commitment to quality, safety, and client satisfaction. With a focus on meticulous planning and execution, Lanmark has established a strong reputation through their extensive portfolio of successful projects. Their expertise is showcased in multi-million dollar constructions, making them a trusted partner for state and municipal agencies.
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 lanmarkgroup.com
— indexed by HaveIBeenRansom.
0
found in Infostealer logs
274+
found in Traditional breaches
20+
found in Ransomware leaks
VerificationsIO_BF.7z.011
Kedr | Forum · breach
••• emails
pureincubation-com.7z.001
Database World ROC · breach
••• emails
OnlinerSpambot_BF.7z
B F R e p o V 3 F i l e s · breach
••• emails
Access Intelligence
play · ransomware
••• emails
Arandell Corp
medusa · ransomware
••• emails
Cit0day [cit0day.in] breaches.csv
LKnet reserve chat · breach
••• emails
Collection1_BF.7z.003
formaceft_db · breach
••• emails
AntiPublic_BF.7z
B F R e p o V 3 F i l e s · breach
••• emails
+ 17 more leak sources locked
Leak volumes are locked
Sign in to reveal how many records each source exposed and the remaining 20 sources.
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.