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

Static analysis result for SHA-256 fd318c245c9d0412…

MALICIOUS

Office (OLE) / .XLS

1.05 MB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel First seen: 2023-08-08
MD5: bac499bcf911292fb5ee476a765310e2 SHA-1: 3395c26ac273b9a7a8d9aad96fe65be1f4c26449 SHA-256: fd318c245c9d0412c1f4614a59b381510e6b2373bf0cf66466e9a63e9ee32663
392 Risk Score

Malware Insights

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

MITRE ATT&CK
T1204.002 Malicious File T1566.001 Spearphishing Attachment T1204 User Execution T1059.005 Visual Basic

The file is an Excel spreadsheet containing an embedded Equation Editor object that exploits CVE-2017-11882. This object contains a secondary PDF payload which, in turn, contains a direct link to a payload. The ClamAV detection name 'Xls.Downloader.94c25b356b5a6cac-9978798-0' further supports its role as a downloader. The embedded PDF also exhibits parser evasion techniques and a direct payload link, indicating a multi-stage infection chain.

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
a10802ef9c4fd54110f88accfd0359cc1ce3f6983b81888a6d9325078bfad6cf
ole-package OLE Ole10Native stream: MBD00304C01/OlE10NATivE 1835 bytes
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
52ede4f57bafda9ec0534b6c2e20ac59532eaf1b3dc11623d595ec5b611f2d95
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x1000 1093632 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off00006200.pdf
a7041ef47b215656113c31c2a33a76e4710240f1945bf259233533e781297ca2
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x6200 1072640 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off0000e400.pdf
ab82dd5d90c44052a231d12d6b52ef3fe8bb934f38d89855cc3a6844c6e86345
polyglot-child-pdf Secondary PDF body inside ole container at offset 0xE400 1039360 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely
polyglot_child_pdf_off0002d000.pdf
b945b55ecdc2354b632634a63dc6018841b8e18353ee345daa634005098e1268
polyglot-child-pdf Secondary PDF body inside ole container at offset 0x2D000 913408 bytes
Detection
ClamAV: Xls.Downloader.94c25b356b5a6cac-9978798-0
Obfuscation or payload: unlikely