Disclosure context

About Nokoyawa

Nokoyawa is a ransomware group that emerged in December 2022, operating with primarily financial motivations and targeting organizations across multiple sectors including healthcare, non-profit, education, finance, and energy. The group has claimed at least 36 victims since its emergence, with attacks predominantly focused on the United States, Canada, United Kingdom, France, and the Philippines. While detailed technical analysis of Nokoyawa's operations remains limited in public reporting, the group appears to follow conventional ransomware tactics targeting critical infrastructure and essential services sectors. Their targeting of healthcare and educational institutions suggests they operate without the sector restrictions that some other ransomware groups have adopted. Notable campaigns include attacks across their preferred geographic regions, though specific high-profile incidents have not been extensively documented in public threat intelligence reporting from major security firms. As of current reporting, Nokoyawa appears to remain an active threat, though the group's relatively recent emergence means long-term operational patterns and potential law enforcement disruption efforts are still developing. The group has been linked to 36 public disclosures across our corpus. First observed on a leak site on December 9, 2022; most recent post October 8, 2023. The operation is currently inactive.

Timeline of this disclosure

May 23, 2023Miescor listed by Nokoyawaon the group's public leak site

Sector and geography

This disclosure adds to ransomware activity in the Energy & Utilities sector, which has 6 disclosures indexed across all operators we track. Geographically, Miescor is reported in Philippines, a country with 6 ransomware disclosures in our corpus.

How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.

Ransomware victim disclosure

← All victims

Meralco Industrial Engineering Services Corporation (MIESCOR)

listed as Miescor · Claimed by Nokoyawa · listed 3 years ago

36m

Age

since listed · data leaked

Status timeline

Listed
May 23, 2023
Data leaked

At a glance

Group: Nokoyawa
Status: Data leaked
Country: Philippines
Sector: Energy & Utilities
Listed on leak site: May 23, 2023

About the victim

AI dossier — public-source company profile

Meralco Industrial Engineering Services Corporation (MIESCOR) is a wholly owned subsidiary of Manila Electric Company (Meralco), the largest electric distribution utility in the Philippines. Incorporated in December 1973, MIESCOR provides industrial engineering services in support of Meralco's operations. It operates within the Philippines' critical energy and utilities sector.

Industry: Electrical Engineering & Utility Services
Founded: 1973

Attack summary

Severity: high — MIESCOR is a subsidiary of the Philippines' largest electric distribution utility, placing it within critical infrastructure. The disclosed status of 'data_published' confirms exfiltration and public release of data, representing a significant breach of a critical energy sector entity even without a stated data volume.

The Nokoyawa ransomware group claims to have attacked MIESCOR and has published data as part of a disclosed leak, though specific details on encryption or the volume of exfiltrated data were not stated in the truncated post.

high

What the group claims

Incorporated in December 1973 as a wholly owned subsidiary of Manila Electric Company (Meralco), the largest electric distribution utility firm in the Philippines, Meralco Industrial Engineering Services Corporation (MIESCOR) has chalked up an exemplary record of engineering performance backed by a...

Sources

Victim sitemiescor.com.ph
Leak posthttp://nokoleakb76znymx443veg4n6fytx6spck6pc7nkr4dvfuygpub6jsid.onion/leak/63acb4be0cc2cef7f87770a4

Source

Indexed 3 years ago

This page surfaces a public ransomware disclosure indexed by Darkfield. Original posts come from the operator's own leak site; we cross-check against ransomware.live, RansomLook and RansomWatch where applicable. Share this URL freely.