Hackers Turn Windows Shadow Copies Into a Tool for Credential Theft and Ransomware
Attackers abuse Windows VSS shadow copies to delete recovery points before ransomware and to extract NTDS.dit/SAM credentials, demanding context-aware detection.
Threat actors are weaponizing the Volume Shadow Copy Service (VSS) for two purposes: destroying local recovery points via vssadmin.exe, wmic.exe, diskshadow.exe, wbadmin.exe, and bcdedit.exe before encryption, and accessing static copies of locked files such as NTDS.dit and SAM for credential theft. Ransomware families tied to shadow-copy removal include Akira, Black Basta, BlackCat, Conti, LockBit, Qilin, RansomHub, REvil, Ryuk, and WannaCry. Huntress's analysis of the Nightmare-Eclipse tool showed the BlueHammer technique chaining a Windows Defender timing issue with a VSS snapshot to dump the SAM database and decrypt NT hashes. Defenders should correlate VSS operations with parent process, hive access, and subsequent encryption activity, and maintain immutable off-host backups.
ZDI-26-645: Fortinet FortiSandbox write_remote_backup_to_crontab cronValue Command Injection Remote Code Execution Vulnerability
ZDI publishes ZDI-26-645 for CVE-2026-84387, an authenticated command injection RCE in Fortinet FortiSandbox via crontab backup, rated CVSS 7.2.
Zero Day Initiative published advisory ZDI-26-645 describing a command injection flaw in Fortinet FortiSandbox's write_remote_backup_to_crontab function. Remote authenticated attackers can execute arbitrary code through the cronValue parameter. ZDI rated the issue CVSS 7.2 and assigned CVE-2026-84387.
Cron Job Injection in Remote Backup
Fortinet FortiSandbox command injection flaw (CVSS 6.7) in remote backup cron jobs lets privileged attackers execute arbitrary code via crafted HTTP requests.
Fortinet advisory FG-IR-26-167 discloses a command injection vulnerability (CWE-77, CVSSv3 6.7) in FortiSandbox's remote backup cron job functionality. A privileged attacker can execute unauthorized code or commands via crafted HTTP requests. The advisory was revised on 2026-09-08.
Hackers Abuse VSSAdmin to Extract NTDS.dit and Delete Windows Recovery Copies
Huntress details intruders using PsExec and VSSAdmin on domain controllers to steal NTDS.dit credentials and delete shadow copies before ransomware.
Huntress analysts identified attackers launching SYSTEM-level command shells via PsExec on a domain controller, then running 'vssadmin create shadow' to snapshot and copy the NTDS.dit Active Directory database. Shadow copies were later deleted to destroy local recovery options ahead of a likely ransomware stage. Huntress recommends correlating VSS creation/deletion events with remote execution, DNS enumeration, and lateral movement rather than alerting on any single VSS event.