Hackers Deploy Hundreds of AI Agents to Compromise 440 PaperCut Servers
AI-agent campaign exploited PaperCut CVE-2026-81578 and CVE-2026-82078, compromising 440 servers at 395 organizations and reaching Domain Admin in 12.
GreyNoise tracked a likely Russian-speaking actor that used AI agents (OpenAI Codex, a DeepSeek model) to exploit an authentication bypass (CVE-2026-81578) and unsafe-reflection RCE (CVE-2026-82078) in PaperCut NG/MF starting August 31, 2026. At least 440 servers across 395 organizations in 48 countries were compromised, with one US high school going from initial access to Domain Admin in seven minutes. Escalation relied on LSASS and registry credential harvesting, pass-the-hash, the noPac technique (CVE-2021-42278/CVE-2021-42287), new Domain Admin accounts, and DCSync to steal NTDS.DIT data. Operators staged registry hives, used Ligolo tunneling and certutil Base64 encoding for exfiltration, and one attempt was blocked by Cloudflare WAF.
Rogue ScreenConnect Installations Across Unrelated Hosts Suggest Worm-Like Activity
Huntress observed rogue ScreenConnect deployments with worm-like VBScript propagation across unrelated organizations, prompting a ConnectWise advisory on file transfer behavior.
Huntress identified multiple incidents in late August 2026 where social engineering led to rogue ScreenConnect remote access clients deployed on victim machines, which then spawned wscript.exe to run four VBScript payloads (1.vbs through 4.vbs) for profiling, telemetry collection, and persistence via a WindowsServiceHost Run key. Modified ScreenConnect clients propagated the VBScript chain to connected endpoints, creating worm-like spread. ConnectWise published an advisory on September 3, 2026, confirming an issue affecting file transfer behavior in both cloud and on-premises ScreenConnect deployments, with a CVE and fix expected within the week; partners were advised to review and disable TransferFiles permissions in the interim.
Novel Blue Moon kit targeting Chrome and Windows reflects new reality of AI-driven exploits
Proofpoint reports the BlueMoon exploit kit, chaining two Chrome V8 zero-days and a Windows ALPC bug, being shared across China-linked espionage groups.
Proofpoint identified a new exploit kit, BlueMoon, first observed on August 28 and used by TA412 (APT31/Violet Typhoon) against US NGOs, mining firms, and commodity trading companies. The kit chains a V8 type confusion RCE (CVE-2026-85046), a V8 sandbox escape, and a Windows Advanced Local Procedure Call privilege escalation (CVE-2026-85880), both patched flaws having been exploited in the wild. At least four espionage groups, most with suspected China nexus including UNK_LateNight, adopted the kit within days, targeting US aerospace firms with defense-sector lures. Fewer than 20 organizations were observed targeted, and researchers believe AI-assisted exploit development against upstream Chromium patches enabled the kit's rapid creation and sharing.
CVE-2026-34486: Apache Tomcat EncryptInterceptor Fail-Open Bypass
Technical analysis shows CVE-2026-34486 is a one-line fail-open regression in Tomcat Tribes enabling unauthenticated RCE via Java deserialization.
CVE-2026-34486 is a fail-open regression in Tomcat's Tribes EncryptInterceptor, introduced while fixing the CVE-2026-29146 padding-oracle flaw; Apache rated it Important and NVD scores it 7.5 High. Decryption failures are now forwarded to an unfiltered ObjectInputStream, and public PoC repositories demonstrate unauthenticated RCE on default port 4000 when clustering, the EncryptInterceptor, a reachable receiver and deserialization gadgets are all present. Affected releases 9.0.116, 10.1.53 and 11.0.20 are fixed in 9.0.117, 10.1.54 and 11.0.21; Tomcat 8.5 is unaffected.
Attackers Chain Two PaperCut Flaws to Execute Code Without Authentication
Attackers chain PaperCut NG/MF flaws CVE-2026-81578 and CVE-2026-82078 for unauthenticated RCE; exploitation observed and a second emergency patch issued.
Two flaws in PaperCut NG and MF — CVE-2026-81578 (CVSS 8.8, improper access control enabling auth bypass) and CVE-2026-82078 (CVSS 9.4, unsafe dynamic class loading) — are being chained for unauthenticated remote code execution. Huntress observed limited exploitation on two customer environments, including Base64-encoded commands, 'whoami & ver' fingerprinting, SimpleHelp execution, and AnyDesk installation for persistence. PaperCut released a second emergency patch for v24, v25, and v26, but watchTowr reports additional patch bypasses may still affect the latest version. Shared IoCs include crafted jdbc strings in server.log and attacker-written .class/.cmd files.
Attackers plant remote access tools on compromised PaperCut servers
Attackers chained two PaperCut NG/MF zero-days for unauthenticated access, installing SimpleHelp and AnyDesk remote access tools on compromised servers.
An ongoing campaign exploits chained zero-days CVE-2026-81578 (improper access control) and CVE-2026-82078 (unsafe dynamic class loading) in internet-facing PaperCut NG and MF Application Servers, enabling authentication bypass and arbitrary Java bytecode execution. Post-compromise activity includes user and domain enumeration, payload download from sendit.sh, and silent installation of SimpleHelp and AnyDesk for redundant remote access; Defused observed CVE-2026-81578/CVE-2026-82078 exploit activity in honeypots since August 29, including data theft via Derby database dumps. Emergency patches were released August 28 and August 30, but 47% of roughly 2,500 PaperCut installs tracked by Huntress run v23 or older, for which no patch is available.
AI-Generated Exploit Scripts Target Siemens S7 PLCs in U.S. Critical Infrastructure
NSA, CISA, FBI, DOE and EPA warn that actors use AI-generated Python scripts to exploit internet-exposed Siemens S7 PLCs at U.S. critical infrastructure.
A joint advisory from NSA, CISA, FBI, DOE and EPA describes an active threat in which AI-generated exploit scripts disguised as legitimate monitoring tools target Siemens S7 Series PLCs (S7-200 through S7-1500, including F-series safety controllers). The actors use Censys and ZoomEye scanning to find internet-exposed, outdated PLCs and a custom Python script using snap7 libraries over the S7comm protocol for initial access, credential access and denial of service; no attribution was given. Targeted sectors include Critical Manufacturing, Energy, Water and Wastewater, Chemical, Food and Agriculture, and Commercial Facilities, with potential for process disruption and cascading impacts. A related Dream report details a near-autonomous AI-agent campaign (July 1-4, 2026, 12 waves) against Taiwan government entities, using Hermes and OpenClaw agents with eight parallel sub-agents to crack 85 accounts via password spraying and exfiltrate over 2,564 personnel records, SSO client secrets and database credentials.