Coverage › CVE-2025-21418

CVE-2025-21418 Mapped Sigma

Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability

Vendor / product

Microsoft — Windows

Description (CISA)

Microsoft Windows Ancillary Function Driver for WinSock contains a heap-based buffer overflow vulnerability that allows for privilege escalation, enabling a local attacker to gain SYSTEM privileges.

Added to KEV

2025-02-11

Due date

2025-03-04

Required action

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

Known ransomware use

Unknown

CWE

CWE-122

CISA notes

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418
https://nvd.nist.gov/vuln/detail/CVE-2025-21418

Elsewhere

cve.org · NVD · CISA KEV · JSON

ATT&CK techniques · CTID Mappings Explorer, ATT&CK 16.1, KEV snapshot 2025-07-28

3 mapping objects across 3 techniques. exploitation technique states how the vulnerability is exploited; primary and secondary impact state what exploitation achieves. They are different claims and are labelled as such.

Detection chain · ATT&CK Enterprise v19.2 detection strategies, analytics, log sources

T1005 Data from Local System primary impact

• DET0380 Detection of Local Data Collection Prior to Exfiltration
  AN1070 Windows

  Adversaries collecting local files via PowerShell, WMI, or direct file API calls often include recursive file listings, targeted file reads, and temporary file staging.

  WinEventLog:Security EventCode=4688 → DC0032 Process Creation

  WinEventLog:Sysmon EventCode=11 → DC0039 File Creation

  Tunable: TargetFilePathRegex ParentProcessFilter
  AN1071 Linux

  Adversaries using bash scripts or tools to recursively enumerate user home directories, config files, or SSH keys.

  auditd:SYSCALL open → DC0055 File Access

  auditd:SYSCALL execve → DC0032 Process Creation

  Tunable: TimeWindow ScriptToolName
  AN1072 macOS

  Adversary use of bash/zsh or AppleScript to locate files and exfil targets like user keychains or documents.

  macos:unifiedlog process:spawn → DC0032 Process Creation

  fs:fsusage read/write → DC0055 File Access

  Tunable: UserContext TargetVolume
  AN1073 Network Devices

  Collection of device configuration via CLI commands (e.g., show running-config, copy flash, more), often followed by TFTP/SCP transfers.

  networkdevice:cli command logging → DC0064 Command Execution

  Tunable: CommandScope AuthenticatedUserList
  AN1074 ESXi

  Adversaries accessing datastore or configuration files via vim-cmd, esxcli, or SCP to extract logs, VMs, or host configurations.

  esxis:vmkernel Datastore Access → DC0055 File Access

  esxi:hostd Command Execution → DC0064 Command Execution

  Tunable: AccessPathRegex InteractiveShellUsage

Sigma rules tagged attack.t1005 (14)

T1055 Process Injection primary impact

• DET0508 Behavioral Detection of Process Injection Across Platforms
  AN1399 Windows

  Detects process injection by correlating memory manipulation API calls (e.g., VirtualAllocEx, WriteProcessMemory), suspicious thread creation (e.g., CreateRemoteThread), and unusual DLL loads within another process's context.

  WinEventLog:Sysmon EventCode=10 → DC0035 Process Access

  WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation

  WinEventLog:Sysmon EventCode=7 → DC0016 Module Load

  etw:Microsoft-Windows-Kernel-Process API calls → DC0021 OS API Execution

  Tunable: AccessMask TimeWindow InjectedProcessList
  AN1400 Linux

  Detects ptrace- or memfd-based process injection through audit logs capturing system calls (e.g., ptrace, mmap) targeting running processes along with suspicious file descriptors or memory writes.

  auditd:SYSCALL ptrace, mmap, process_vm_writev → DC0021 OS API Execution

  auditd:SYSCALL open → DC0055 File Access

  linux:procfs /proc/[pid]/maps, /proc/[pid]/mem → DC0020 Process Modification

  Tunable: TargetPIDThreshold TimeWindow
  AN1401 macOS

  Detects memory-based injection by monitoring task_for_pid, mach_vm_write, and dylib injection patterns through DYLD_INSERT_LIBRARIES or manual memory mapping.

  macos:unifiedlog subsystem=com.apple.security, library=libsystem_kernel.dylib → DC0035 Process Access

  macos:endpointsecurity ES_EVENT_TYPE_NOTIFY_EXEC, ES_EVENT_TYPE_NOTIFY_MMAP → DC0034 Process Metadata

  macos:syslog DYLD_INSERT_LIBRARIES anomalies → DC0016 Module Load

  Tunable: TargetProcessSignature MachSyscallContext

Sigma rules tagged attack.t1055 (37)

All 37 rules on the technique page →

T1068 Exploitation for Privilege Escalation exploitation technique

• DET0514 Detection Strategy for Exploitation for Privilege Escalation
  AN1419 Windows

  Detects exploitation attempts targeting vulnerable kernel drivers or OS components, often followed by unusual process or token behavior.

  WinEventLog:Sysmon EventCode=6 → DC0079 Driver Load

  WinEventLog:Sysmon EventCode=1 → DC0032 Process Creation

  WinEventLog:Security EventCode=4672 → DC0088 Logon Session Metadata

  Tunable: DriverNamePattern TimeWindow ParentProcessPath
  AN1420 Linux

  Detects escalation via vulnerable setuid binaries or kernel modules, often chained with unusual access to /proc/kallsyms or /dev/kmem.

  auditd:SYSCALL execve → DC0032 Process Creation

  auditd:SYSCALL ACCESS → DC0035 Process Access

  auditd:SYSCALL dmesg → DC0016 Module Load

  Tunable: SetUIDBinaryList TimeWindow EffectiveUIDThreshold
  AN1421 macOS

  Detects use of vulnerable kernel extensions or entitlements abused via setuid or AppleScript injection chains.

  macos:unifiedlog process:exec and kext load events → DC0032 Process Creation

  macos:endpointsecurity ES_EVENT_TYPE_NOTIFY_KEXTLOAD → DC0016 Module Load

  Tunable: EntitlementList TimeWindow
  AN1422 Containers

  Detects container breakout behavior via exploitation (e.g., DirtyPipe, CVE-2022-0847), followed by host OS interaction or escalated capability assignment.

  auditd:SYSCALL capset or setns → DC0067 Logon Session Creation

  containerd:runtime e.g., containerd, Docker events → DC0091 Container Enumeration

  Tunable: NamespaceEscapePattern TimeWindow

Sigma rules tagged attack.t1068 (31)

All 31 rules on the technique page →