hippamsascom: 9a3c18be — Littel LLC "wireless sensor" masquerade sibling

Executive Summary

A third sibling in the hippamsascom MSVC x64 self-loading dropper cluster, masquerading as "wireless sensor Standard Manager" by "Littel LLC". Shares the same build/RE fingerprint with prior siblings (semantic export obfuscation, zero IAT, PEB-walking API resolution, custom stream-cipher payload decryption, fabricated Authenticode intermediate CA) but rotates the masquerade identity and certificate branding per campaign. Static-only analysis; no CAPE detonation available.

What It Is

Version info claims CompanyName: Littel LLC, ProductName: wireless sensor, FileDescription: wireless sensor Standard Manager, OriginalFilename: littel-wirelesssensor.exe, InternalName: wirelesssensor.exe ^[exiftool.json]. This is a new masquerade identity distinct from the prior siblings (Emard LLC / "JBOD monitor" and Hane Group / "redundant alarm").

How It Works

1. Entry gate — entry0 calls a parent-process sandbox gate (fcn.140034820). If the gate fires, the binary aborts with -1; otherwise it proceeds to the self-loader. ^[r2:entry0]
2. API resolution — Zero imports. All Win32 APIs are resolved at runtime via PEB-walking (fcn.140034430): walk InMemoryOrderModuleList, hash exported names with a DJB2-like routine (fcn.1400344f0), match hardcoded 32-bit hashes (e.g., 0x4d876dd2, 0x680c1e94, 0xac4adf9d). ^[r2:fcn.140034430], ^[r2:fcn.1400344f0]
3. Payload decryption — The encrypted payload lives in the .data section (entropy 7.97, size 0xD775C ≈ 885 KB). Decryption is a multi-stage custom stream cipher:
   • fcn.140031b00: first-stage key-schedule using SHA-256-like mixing constants (0x6a09e667, 0xbb67ae85, etc.) and lookup tables from .rdata. ^[r2:fcn.140031b00]
   • fcn.1400332d0: second-stage block shuffler / Feistel-like round function operating on 1024-byte blocks with per-round index-dependent XOR, rotate, and add operations. ^[r2:fcn.1400332d0]
   • fcn.1400330e0: third-stage lightweight byte-mixer used on residuals. ^[r2:fcn.1400330e0]
4. Self-loader / manual PE mapping — fcn.1400349e0 performs full in-memory PE mapping of the decrypted payload:
   • Checks MZ/PE headers.
   • Allocates RWX memory (VirtualAlloc style, resolved via hash 0x5da08862).
   • Copies sections, processes relocations, resolves imports via the same PEB hash resolver.
   • Fixes memory permissions (VirtualProtect-style).
   • Calls the payload entry point. ^[r2:fcn.1400349e0]
5. Export façade — 330 exported names (0x14A) map to only 19 unique RVAs, all tiny stubs. Names are semantically plausible jargon (AbortWaitChecksum, BackendCalculateItem, CertificateNode, etc.). ^[pefile.txt:338+], ^[r2:exports]

Decompiled Behavior

entry0 (0x1400341d0)

Prologue: allocate stack frame, call sandbox gate. If gate fails, return -1. On success, call fcn.140034920 (the self-loader orchestrator) and exit cleanly. ^[r2:entry0]

fcn.140034920 (self-loader orchestrator)

Resolves the memory-allocation API hash (0x5da08862, VirtualAlloc equivalent), allocates a buffer of size 0xcee00 (843,264 bytes), copies ciphertext from .data at RVA 0x39100, then invokes the three-stage decryptor (fcn.1400332d0). After decryption, hands off to fcn.1400349e0 for PE mapping / execution. ^[r2:fcn.140034920]

fcn.1400349e0 (manual PE mapper)

Classic reflective loader logic: walk PE headers, allocate memory at ImageBase or fallback, copy sections, process .reloc entries, resolve imports by name-hash, set proper section permissions, zero PE headers, and transfer control. No disk write occurs. ^[r2:fcn.1400349e0]

Notable control-flow patterns

• Heavy use of cmov and bit-masking for conditional branching without explicit jumps, complicating decompilation.
• All crypto routines reference lookup tables in .rdata at offset 0x36000 / 0x36020, making static key extraction impossible without the full binary.

C2 Infrastructure

• Static C2: None observable in plaintext strings or decrypted stubs. The payload is fully encrypted and C2 is likely resolved at runtime by the second-stage payload (not available statically).
• Certificate domains (from Authenticode blob): www.littelllc.tech, www.littelllc-elsie.tech, www.littelllc-mallie.global, www.littelllc-tess.group, ca.littelllc.tech, intermediate.littelllc.tech ^[strings.txt:2130-2139]
• Email: digitaltrust@littelllc.tech ^[strings.txt:2102]
• OCSP/CRL endpoints: DigiCert legitimate infrastructure (ocsp.digicert.com, crl3.digicert.com) — the leaf cert chain is cross-signed to the real DigiCert root, making the forgery superficially valid. ^[strings.txt:2091-2093]

Interesting Tidbits

• The intermediate CA is named "Littel LLC Intermediate CA 2" with claimed locality "North Lucie, Texas" and org unit "Port Telly LLC Systems" — all fictional but consistent across the cert chain. ^[strings.txt:2107]
• .rsrc contains a 256×256 PNG icon and an XML UAC asInvoker manifest, reinforcing the "legitimate software" appearance. ^[binwalk.txt]
• ShellExecuteW is resolved at runtime (hash not yet identified), suggesting the decrypted payload may be launched as a child process or the loader itself may drop additional files. ^[strings.txt:2020]
• The export-name vocabulary has shifted slightly toward networking / DevOps jargon (DecompressPayload, RegistryCodeTransaction, QueuePropertiesCertificate, BackendCalculateItem, ClusterManager) compared to earlier siblings, but the mechanics are identical.

How To Mess With It (Homelab Replication)

1. Toolchain: Visual Studio 2022 (MSVC 14.50), x64 Release.
2. Build a zero-IAT PE: Link with /NODEFAULTLIB, write your own DllMain-style entry, resolve APIs via PEB walking.
3. Embed a payload: Use objcopy or a simple resource script to embed an encrypted PE in .data.
4. Encrypt with a stream cipher: Implement a multi-round Feistel-like function with per-round XOR/rotate/add and a 256-byte S-box from .rdata.
5. Add semantic exports: Generate 300+ compound names mapping to 20 ret-only stubs with a .def file.
6. Forge a cert chain: Use OpenSSL to create a leaf cert with fake intermediate CA and cross-sign to a real DigiCert root (for testing only).
7. Verification: Run capa on the reproducer; it should flag "obfuscated files or information" and "resolve API by hashing" even without the real signatures installed.

Deployable Signatures

YARA

rule hippamsascom_littel_sibling
{
    meta:
        author = "titus"
        description = "hippamsascom dropper with Littel LLC masquerade"
        date = "2026-06-15"
        sha256 = "9a3c18be39571b479c7ee37d32f6000725a282abdf04643a1edfec460876762b"
    strings:
        $littel1 = "Littel LLC" ascii wide
        $littel2 = "wireless sensor" ascii wide
        $littel3 = "littel-wirelesssensor.exe" ascii wide
        $littel4 = "digitaltrust@littelllc.tech" ascii
        $littel5 = "www.littelllc.tech" ascii
        $littel6 = "Port Telly LLC Systems" ascii
        $dll1 = "kernel32.dll" ascii
        $dll2 = "shell32.dll" ascii
        $dll3 = "ole32.dll" ascii
        $api1 = "LoadLibraryA" ascii
        $api2 = "GetProcAddress" ascii
        $api3 = "ShellExecuteW" ascii
    condition:
        uint16(0) == 0x5A4D and
        pe.is_pe and
        pe.number_of_exports > 250 and
        pe.exports_index[0].rva > 0 and
        pe.imports("") == none and
        3 of ($littel*) and
        3 of ($dll*) and
        2 of ($api*)
}

Sigma (Behavioral Hunt)

title: hippamsascom Self-Loader Execution
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        CommandLine|contains:
            - 'Oyster.exe'
            - 'wirelesssensor.exe'
            - 'littel-wirelesssensor.exe'
    selection_api:
        - CallTrace|contains: 'kernel32.dll'
        - CallTrace|contains: 'shell32.dll'
    condition: selection or selection_api
falsepositives:
    - None expected for the specific filenames; the masquerade names are unique to this campaign.
level: critical

IOC List

Behavioral Fingerprint

This binary is a 64-bit Windows PE with an empty IAT and 300+ exported names resolving to fewer than 20 tiny stubs. At runtime it resolves Win32 APIs by walking the PEB InMemoryOrderModuleList and matching DJB2-like name hashes. It then decrypts an 800+ KB payload embedded in the .data section using a multi-stage custom stream cipher (SHA-256-like key schedule, 1024-byte block shuffler, byte mixer) and manually maps the decrypted PE into newly allocated RWX memory, processes relocations, resolves imports by hash, fixes permissions, and transfers control. The binary carries a fabricated Authenticode certificate chain claiming "Littel LLC" with SANs across multiple .tech, .global, and .group domains, cross-signed to the real DigiCert root. No disk write of the payload is observed; execution is fully reflective.

Detection Signatures

References

• hippamsascom — family entity page
• sunwukong — co-labeled sibling cluster (same build pattern, different masquerade identity)
• semantic-jargon-export-obfuscation — technique page for export table flooding
• peb-walking-api-resolution — technique page for runtime API resolution
• version-info-masquerade — technique page for VS_VERSIONINFO masquerade
• MalwareBazaar: 9a3c18be39571b479c7ee37d32f6000725a282abdf04643a1edfec460876762b

Provenance

Analysis derived from static artifacts generated by the triage pipeline:

• file.txt — file(1) output
• exiftool.json — ExifTool metadata extraction
• pefile.txt — pefile.py structural dump
• strings.txt — raw ASCII/Unicode strings
• floss.txt — FireEye flare-floss (error — no decoded strings)
• capa.txt — Mandiant capa (error — missing signatures)
• binwalk.txt — embedded artifact scan
• rabin2-info.txt — radare2 binary header summary
• dynamic-analysis.md — CAPE sandbox status (skipped, no Windows guest available)
• radare2 decompilation at analysis level 4 — functions entry0, fcn.140031ab4, fcn.140031b00, fcn.140032d00, fcn.1400330e0, fcn.1400332d0, fcn.140034430, fcn.1400344f0, fcn.140034920, fcn.1400349e0
• pyghidra import queued but analysis incomplete at time of writing; radare2 provided primary decompilation.