Malicious PDF — malware analysis report

Static analysis result for SHA-256 b8b816c99422b983…

MALICIOUS

PDF

43.4 KB Created: 2020-06-13 19:17:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: f12de9c16ae1b603cb6766b57bfc0317 SHA-1: 2f833752713f92aedf7064248d130f1f094c5b1b SHA-256: b8b816c99422b9833f3719f39b82243526ef6e4a0a230b1fa9315cabdb1f9c1a
94 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious Link

The PDF document contains a large number of external links, identified by the PDF_SEO_LINK_FARM heuristic. The document body text, though partially corrupted, includes a URL that points to a page with 'exercicios resolvidos', suggesting a lure. The ML classifier strongly flagged this PDF as malicious, indicating a high probability of malicious intent behind the link farm. No scripts were extracted from this sample.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9999

Heuristics 4

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • External URI info PDF_URI
    PDF contains an external URL action
  • 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 http://aa.undesirable.us/uploads/1/3/0/7/130776405/130776405.html#equa%25C3%25A7%25C3%25A3o+fatorial+exercicios+resolvidos
    • http://zumarock.org/uploads/1/3/0/7/130739967/wawebusin.pdf
    • http://chatmanvirtualbooktours.com/uploads/1/3/1/4/131483278/7b95cf7d717f9d.pdf
    • http://begreatapparel.com/uploads/1/3/0/7/130740053/8830342.pdf
    • http://myburialinsurance.com/uploads/1/3/1/8/131871854/wilis.pdf
    • http://migromarine.com/uploads/1/3/0/4/130483508/tunawiwebad_lufazu_susomifaladox_dizigidumewerak.pdf
    • http://elitepaintingcleaningandmore.com/uploads/1/3/0/5/130589072/sikomaxuwegufin.pdf
    • http://paragonsolutionsselect.com/uploads/1/3/0/8/130813899/lirewurorenamugabak.pdf
    • http://3577productions.com/uploads/1/3/1/3/131382693/1551866.pdf
    • http://74-123-73-221.mgwnet.com/uploads/1/3/1/6/131636833/vuromifob_nigajomoxune_gifubasufu_xuwenufulorekil.pdf
    • http://billy-nelson.com/uploads/1/3/0/3/130313107/1ce1c1ce.pdf
    • http://hanamakeup.studio/uploads/1/3/1/4/131455956/leposotilirem.pdf
    • https://gomepimus.files.wordpress.com/2020/06/11493410632.pdf
    • https://zomoxazira.files.wordpress.com/2020/06/80121647186.pdf
    • https://zijumaxiwigu.files.wordpress.com/2020/06/47872479862.pdf
    • https://derexomej.files.wordpress.com/2020/06/lutavave.pdf
    • https://mumomajolope.files.wordpress.com/2020/06/48934037661.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000664e.bin
e24fa3f9371708e176a9973c36b5328fdc4b8b7a280e6229387aa9fc766172de
pdf-font-stream PDF embedded font (sfnt) at offset 0x664E 12328 bytes
font_01_sfnt_off00008d02.bin
3bb08857b08983a257d5a2052628e18542fd51c8d29f5bbef87ea8b8ace00841
pdf-font-stream PDF embedded font (sfnt) at offset 0x8D02 16096 bytes