Xls.Downloader.94c25b356b5a6cac-9978798-0 — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 7ef57b4182fe29e7…

MALICIOUS

Office (OLE) / .XLSX

1.27 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-08-15
MD5: b9978336180c99d08ce3e6445d285cf8 SHA-1: 514d1897f6e0bdfb5c0fe1bd9271a6c7074263d1 SHA-256: 7ef57b4182fe29e7281171c8ac9c21a7f91c3251da992523ef6e69b11faa60a7
392 Risk Score

Malware Insights

Xls.Downloader.94c25b356b5a6cac-9978798-0 · confidence 95%

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file contains an embedded Equation Editor OLE object that exploits CVE-2017-11882. This object contains a secondary PDF payload which, in turn, links to an external URL. The ClamAV detection name 'Xls.Downloader.94c25b356b5a6cac-9978798-0' suggests a downloader functionality, likely initiated by the embedded PDF.

Heuristics 10

  • Equation Editor Ole10Native payload — CVE-2017-11882 critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    An embedded Microsoft Equation 3.0 object (CLSID 0002CE02-0000-0000-C000-000000000046) carries an Ole10Native packager stream instead of the normal Equation Native/MTEF data. This is the weaponized Equation Editor RCE delivery shape used by CVE-2017-11882 / CVE-2018-0802 maldocs. The payload (font-record overflow + shellcode) is frequently encrypted and the stream name case-scrambled to evade scanners, but an Equation object holding an Ole10Native stream has no benign use.
  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Contains Equation Editor object — related to CVE-2017-11882 / CVE-2018-0802 exploitation, but CLSID presence alone is not the malformed MTEF exploit primitive.
  • Secondary embedded PDF body has suspicious static findings critical POLYGLOT_CHILD_PDF_STATIC_TRIAGE
    A valid PDF body was found at a nonzero offset inside another container and its carved contents matched PDF exploit or lure heuristics. This catches polyglots where the top-level magic routes to ZIP/OLE while a PDF reader or downstream parser opens the hidden PDF payload.
  • PDF link points directly to executable/archive payload critical PDF_DIRECT_PAYLOAD_LINK
    PDF contains a clickable HTTP(S) URI whose path ends in an executable, script, shortcut, disk image, or archive extension. Documents can legitimately link to installers, so this is a high-risk delivery indicator rather than a standalone exploit fingerprint.
  • ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.94c25b356b5a6cac-9978798-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Clickable PDF combines external action with parser-evasion structure high PDF_ACTION_PARSER_EVASION
    PDF has an external clickable URI together with object graph or xref structures that make parsers disagree, such as divergent duplicate objects, parser divergence, or xref offset mismatch. That combination is stronger than a plain link: the document is both an outward-action carrier and a parser-confusion/evasion sample.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://https://www.google.co.in/example.com
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://ns.adobe.com/xap/1.0/
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/pdf/1.3/

Extracted artifacts 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7f506327609c082af1cd37dde23bc2c71a000f7d1ef530b6abb66775040a7673
vba-macro oletools.olevba.extract_macros (decoded VBA source) 1206 bytes
ole10native_00.bin
46f936b373bda627aa6aad8ffd6783c4d90e4799a21ac713feb5ca6a281ffbee
ole-package OLE Ole10Native stream: MBD0040CE24/Ole10nAtiVe 1344 bytes
polyglot_child_pdf_off00076c00.pdf
54e2aee87255121596f63c21c34e78c8ca977ff8d696ed1df2174fec1b648b89
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x76C00 843264 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
font_00_sfnt_off0000817d.bin
68d167e68895a344f3603a4efd0d8438eb8fdebe759cee48f2b4adf75c76c961
pdf-font-stream PDF embedded font (sfnt) at offset 0x817D 12100 bytes
font_01_sfnt_off00009f95.bin
50551000b9f90b3f445ee94749557d9ddf96697a74984b3ccf3d2bae66910750
pdf-font-stream PDF embedded font (sfnt) at offset 0x9F95 15820 bytes
polyglot_child_pdf_off00001000.pdf
81b66645e980d100af033d7f0223a377342ddaf6b15b347b683b96ca31437cc0
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x1000 1325568 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off00006200.pdf
8358e8e4b7f9009b04883375f476f01c9c6d00176a0909b9ce88cb111ffdcb16
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x6200 1304576 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off0000e600.pdf
2aba632a98d9218867ccb47214b872a9cd3a0423036fec803e208e1458e6656c
polyglot-child-pdf Secondary PDF body inside ole container at offset 0xE600 1270784 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely