CVE-2019-15107

In 2025, a Chinese state-linked espionage group hijacked the update channel of Notepad++, one of the most widely installed Windows text editors, to plant a custom backdoor on a handful of carefully chosen targets. The attackers never touched Notepad++'s source code or its signing keys. Instead they compromised the third-party shared-hosting server that delivered updates, and abused the fact that the WinGUp updater shipped without any integrity check on what it downloaded (tracked as CVE-2025-15556). For machines on their target list, WinGUp was silently redirected to attacker-controlled servers that served a trojanized installer; everyone else kept receiving the genuine update. The campaign ran from roughly June to December 2025 and was only made public in February 2026 by Rapid7, with Kaspersky and Broadcom/Symantec corroborating it independently.

On or around January 20, 2026, attackers who had broken into a regional update server for eScan, the antivirus product made by India's MicroWorld Technologies, pushed a trojanized Reload.exe through the legitimate update channel during a window of roughly two hours. The security software itself became the delivery vehicle for malware. The malicious binary carried eScan's code-signing identity, but its signature was actually invalid; it ran anyway because the updater trusted the channel rather than rigorously validating the signature. Once on a host, the malware rewrote the Windows HOSTS file to cut eScan off from its own update servers, blinded script scanning, and reached out to takedown-resistant command-and-control hosted on blockchain naming systems. Morphisec disclosed the campaign, with Kaspersky and Darktrace corroborating it independently.

In September 2017, Cisco Talos revealed that CCleaner, a hugely popular Windows cleanup tool from Piriform (newly acquired by Avast), had been shipping a backdoor. Attackers had compromised Piriform's build environment and inserted malicious code into the official, validly code-signed installer, so version 5.33 distributed through Piriform's own channels carried the malware to about 2.27 million users for roughly a month before anyone noticed. The first stage merely profiled machines, but it was a sniper rather than a shotgun: from the millions of installs it served a second stage to only a few dozen selected computers at companies like Google, Microsoft, Cisco, Intel, and Samsung, and a still deeper espionage tool (the ShadowPad backdoor) was later found planted on Piriform's own internal machines. The attack is linked to the China-nexus group tracked as APT17 / Axiom. It is the lesson that a trusted update channel and a valid signature are not the same as trustworthy code, and that build pipelines are prime targets.

Trojanized pantheon-agents 0.6.1 and 0.6.2 on PyPI ship a credential stealer (supply-chain account compromise)

atomic-agents-stack: HTTP MCP catalog accepts cleartext http and spawns catalog-supplied commands (MITM to RCE)

In June 2026 the npm supply-chain worm finally produced something genuinely new and frightening: malicious packages that were signed and carried valid build provenance. Attackers used a compromised GitHub account inside Red Hat's own organisation to publish trojanised versions of 31 packages in the @redhat-cloud-services namespace through Red Hat's legitimate CI pipeline, so the poisoned releases arrived with authentic attestations proving they were built by the real build system. The payload, nicknamed Miasma, was a lightly re-skinned copy of Mini Shai-Hulud, a worm that a group called TeamPCP had open-sourced for anyone to reuse weeks earlier. No Red Hat customers were harmed, because Red Hat strips install scripts before deployment, but the permanent lesson is uncomfortable: a signature proves where a package was built, not that the build was clean.