ZeroHour

Search: “worm”

15 stories in the last 30d

WeChat Worm Can Hijack Accounts Without Victims Answering Calls

Researchers demoed WeWorm, a zero-click WeChat worm hijacking accounts via incoming VoIP calls using a memory corruption flaw; Tencent patched it in August.

Researchers at Calif exploited a memory corruption bug in WeChat's VoIP system, taking over accounts through an incoming call even if the victim never answers or touches the phone. The attacker must already be a WeChat contact, but compromising a friend's account bypasses this, and chained calls spread the worm across three Android and iOS test phones in seconds. Tencent fixed the flaw in Android 8.0.77 and iOS 8.0.76 released in August, and researchers found no evidence of real-world exploitation. WeChat and Weixin reported 1.418 billion combined monthly active users at the end of 2025.

Security Affairs · 8d agoExploit / PoC

WeWorm – First 0-Click Worm Spreading Through WeChat Calls Across iOS and Android

Researchers demonstrated WeWorm, a zero-click worm exploiting a memory-corruption flaw in WeChat's VoIP stack to spread via calls across iOS and Android.

Security firm Calif published WeWorm, a proof-of-concept zero-click worm exploiting a memory-corruption bug in WeChat's VoIP stack to spread through voice calls on iOS and Android without the victim answering. The demo chained a Pixel 10a, an iPhone 17e, and a second Pixel 10a, compromising each device while the call was still ringing and giving full control of the WeChat account. The attacker must already be on the victim's friend list, but compromised contacts become the propagation layer across a platform with over 1.4 billion monthly users. Calif reported the bug to Tencent in July 2026, and Tencent has since mitigated it; full technical details are withheld for a later conference presentation.

Cyber Security News · 8d agoExploit / PoC

Researchers Build WeChat Zero-Click Worm Hijacking Phones via Calls

Calif researchers built WeWorm, a zero-click worm exploiting a WeChat VoIP memory-corruption RCE that Tencent has now patched.

Calif researchers found a memory corruption flaw in WeChat's VoIP stack in July using LLM-assisted analysis and built working exploits within two days, then integrated them into WeWorm, which they call the first zero-click worm spreading through WeChat calls on iOS and Android. A crafted incoming call yields remote code execution with no user interaction, giving full control of the victim's WeChat account; the attacker only needs to be on the victim's friend list, easily achieved by compromising a contact first. Tencent confirmed the bug and shipped patches in WeChat Android 8.0.77 and iOS 8.0.76, and chaining with other OS bugs could yield full device control.

Infosecurity Magazine · 7d agoExploit / PoC

WeChat worm could pwn a friend before they even answered the call

Calif researchers demoed WeWorm, a zero-click WeChat VoIP memory-corruption worm enabling account takeover; Tencent patched it August 21.

Security firm Calif found a memory corruption bug in WeChat's VoIP stack that let a trusted contact take over a user's account simply by calling them, without the call being answered. The demo worm then called the victim's contacts to self-propagate across iOS and Android; declining the call prevented infection. Tencent pushed fixes on August 21, and Calif said chaining the bug with other Android and iOS flaws could yield full device control. Calif used AI to find the vulnerability and build its first RCE exploit in about two days.

The Register · Security · 7d agoExploit / PoC

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.

Huntress · 13d agoExploit / PoC in the wild1

ConnectWise Patches ScreenConnect Vulnerability Exploited in Worm-Like Attacks

ConnectWise patched critical ScreenConnect flaw CVE-2026-84869 (CVSS 9.9) exploited since August 20 in worm-like attacks; CISA added it to KEV.

ConnectWise released urgent patches for CVE-2026-84869 (CVSS 9.9), a missing authorization and improper privilege management flaw in ScreenConnect allowing file transfer and execution through active remote sessions without host confirmation. Huntress reported in-the-wild exploitation since August 20, with attackers using rogue ScreenConnect clients to push four VBScript files for persistence and worm-like propagation to other ScreenConnect clients. The flaw is fixed in ScreenConnect 26.6.5, with disabling the TransferFiles permission as a temporary mitigation. CISA added the CVE to its KEV catalog, requiring federal agencies to patch within three days under BOD 26-04.

SecurityWeekupdated · 3h agofirst · 2d agoExploit / PoC in the wild 5 sourcesCVE-2026-848691

Modified ScreenConnect Clients Used in Worm-Like Campaign

Huntress warns of worm-like attacks using modified ScreenConnect clients to spread VBScript payloads; ConnectWise issued an advisory.

Campaigns starting in late August use social engineering, including Quick Assist abuse, to install rogue ScreenConnect clients that spawn wscript.exe and deploy four VBScript files for reconnaissance, staging, and PowerShell execution. The attackers persist via User Run Keys, attempt UAC bypass, install UltraViewer, and propagate the VBScript chain to other connected ScreenConnect endpoints. ConnectWise published an advisory about a file transfer behavior issue affecting cloud and on-premises ScreenConnect, with a CVE identifier and fix expected within a week; it recommends disabling file transfer meanwhile.

SecurityWeek · 9d agoExploit / PoC in the wild

Weekly Cybersecurity Newsletter Bulletin – Microsoft 0-day, FortiOS, PAN-OS Flaw, Revolut Data Breach, and 20+ Stories

Weekly roundup: Microsoft patches 973 flaws including two actively exploited zero-days; FortiOS CAPWAP flaw deploys PivotC2 RAT; PAN-OS root RCE disclosed.

Microsoft's September 2026 Patch Tuesday fixed 973 vulnerabilities, including two zero-days under active exploitation: CVE-2026-85880 (Windows ALPC) and CVE-2026-81963 (Windows Update Stack), both elevation-of-privilege bugs. SOCRadar reported active exploitation of CVE-2025-25249 (CVSS 9.8) in FortiOS CAPWAP, deploying a Node.js RAT called PivotC2 that exfiltrates Exchange mailboxes to Wasabi cloud storage; 178 devices were compromised out of 30,000 scanned IPs, attributed to a Russian-speaking financially motivated group. Palo Alto disclosed CVE-2026-0310, a 9.2-rated buffer overflow enabling root code execution on PA-Series firewalls, and Fortinet disclosed CVE-2026-84393, a ZTNA certificate validation MITM flaw. Cyera also revealed CVE-2026-6471 ('PostGREShell'), a 12-year-old PostgreSQL logical-decoding flaw allowing code execution via REPLICATION-privileged accounts.

Week in review: Linux rootkit deployed on F5 BIG-IP APM devices, Cisco FMC bugs exploited

Weekly roundup: Cisco FMC and N-able N-central zero-days exploited in the wild, MikroTik RouterOS hijacks, Microsoft Patch Tuesday ships two exploited zero-days.

State-sponsored and financially-motivated attackers are actively exploiting CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center (FMC), alongside CVE-2026-20316. N-able issued an emergency hotfix for CVE-2026-86218, a critical pre-auth RCE in the N-central RMM platform exploited in the wild. CERT Polska disclosed six RouterOS vulnerabilities being chained to hijack internet-exposed MikroTik devices. Microsoft's September 2026 Patch Tuesday shipped a record patch count including two zero-days, while roughly 67,000 Trezor customers faced phishing after a shipping-partner breach and researchers privately disclosed a zero-click WeChat worm to Tencent.

Help Net Security · 3d agoExploit / PoC in the wildCVE-2026-20079CVE-2026-20316CVE-2026-862182· 1 read

Acronis Patches Exploited Vulnerability in cPanel Backup Plugin

Acronis urgently patched CVE-2026-87886 (CVSS 7.8), insecure file permissions enabling privilege escalation, exploited in targeted attacks on cPanel & WHM backups.

Acronis released urgent patches for CVE-2026-87886 (CVSS 7.8), insecure file permissions in the Backup plugin for cPanel & WHM and the Backup extension for Plesk that allow attackers to gain elevated privileges. Exploitation has been detected in the wild in limited, targeted attacks against the cPanel & WHM plugin, but not against the Plesk extension. All Linux versions of the plugin before build 1.9.3.1021 and the Plesk extension before build 1.8.11.638 are affected; Acronis urges immediate updates and has not shared technical details.

SecurityWeekupdated · 7h agofirst · 8h agoExploit / PoC in the wild 6 sourcesCVE-2026-87886

Root RCE Zero-Day in Cisco Secure Email Gateway Under Active Exploitation

Cisco warns CVE-2026-76461 (CVSS 9.8), an unauthenticated root RCE in Secure Email Gateway AsyncOS, is actively exploited in the wild.

Cisco confirmed that CVE-2026-76461, a CVSS 9.8 email-parsing flaw in Secure Email Gateway AsyncOS, is being exploited in the wild since September 2026, allowing unauthenticated remote attackers to execute arbitrary commands with root privileges via crafted emails containing malicious SQL statements. All physical and virtual SEG configurations are affected; Secure Email and Web Manager and Secure Web Appliance are not. CISA added the flaw to the KEV catalog with a September 17 federal remediation deadline, and Cisco released IoCs while noting root access lets attackers remove them.

SecurityWeekupdated · 4h agofirst · 1d agoExploit / PoC in the wild 17 sourcesCVE-2026-76461CVE-2025-20393CVE-2026-20079+1 CVEs2

BlueMoon Exploit Kit Chains Recent Chrome, Windows Zero-Days

Proofpoint reports multiple espionage groups rapidly adopting BlueMoon, a new exploit kit chaining Chrome and Windows zero-days.

Proofpoint identified a new exploit kit, BlueMoon, chaining two Chrome V8 zero-days (CVE-2026-85046, CVE-2026-87491) with a Windows ALPC privilege escalation zero-day (CVE-2026-85880), all patched between September 3 and September 2026 Patch Tuesday. China-linked Violet Typhoon (APT31) first used it on August 28 against US NGOs and mining/commodity trading firms; UNK_LateNight, UNK_DoubleCheck, and UNK_QuietRacket adopted it within days against targets in the US, Vietnam, Indonesia, and Singapore. The kit exploits the V8 defects for sandbox escape, fingerprints the host, and injects a CreateProcess stub into the Chrome broker process to download and execute a payload via curl. Development artifacts suggest the kit's creators may have used AI to build it, potentially lowering the barrier to exploit development.

SecurityWeekupdated · 1h agofirst · 4d agoExploit / PoC in the wild 19 sourcesCVE-2026-85046CVE-2026-87491CVE-2026-858804

N-able Patches Critical Zero-Day in N-central

N-able patches critical unauthenticated RCE zero-day CVE-2026-86218 in N-central, exploited in the wild; on-premises admins must apply hotfix 2026.3 HF4.

N-able released an urgent hotfix (2026.3 HF4) for CVE-2026-86218 (CVSS 10), an unauthenticated RCE in N-central exploited as a zero-day. Scanning/exploitation attempts observed from IP range 23.234.64.0/18 starting September 4; admins should check logs for scanning and unrecognized new accounts. The hotfix supersedes patches for CVE-2026-86206 and CVE-2026-86207, which Huntress observed potentially chained in the wild to bypass authentication in production environments.

CVE-2026-34908: Ubiquiti Networks UniFi OS Server access control ...

CVE-2026-34908, a CVSS 10.0 access-control bypass in Ubiquiti UniFi OS, was added to CISA's KEV catalog amid reported active exploitation.

CISA added CVE-2026-34908 to the Known Exploited Vulnerabilities catalog on June 23, 2026, with remediation due June 26 under BOD 26-04 guidance. The CVSS 10.0 improper access control flaw (CWE-284) in Ubiquiti UniFi OS allows unauthorized system changes without authentication. Multiple news reports referenced by the page describe the max-severity UniFi flaws being exploited in attacks, and an official patch is available.

Attackers use rogue ScreenConnect clients to spread malware

Attackers deploy rogue ScreenConnect clients that spread VBScript malware to newly connected machines while ConnectWise patches a file-transfer flaw.

ConnectWise confirmed a file transfer flaw in ScreenConnect affecting both Cloud and On-Premise deployments, with a CVE identifier and official fix promised within the week; administrators can mitigate immediately by disabling TransferFiles (or TransferFilesInSession) in each role. Huntress documented incidents where social engineering installs rogue ScreenConnect clients that spawn Windows Script Host processes running four VBScript files (1.vbs-4.vbs), add a WindowsServiceHost registry Run key, and propagate to newly connected endpoints. Payloads enabled host profiling, persistence, additional ScreenConnect installs, tunneling, security-control changes, and cryptocurrency mining. ConnectWise has not confirmed a technical link between the flaw and this campaign.

Help Net Security · 9d agoExploit / PoC in the wild