Malicious PDF — malware analysis report

Static analysis result for SHA-256 bdda87d4f0cfb797…

MALICIOUS

PDF

79.6 KB Created: 2021-09-09 11:25:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 698c679f45bf6dad96c4654054df6bf5 SHA-1: 669528503d9cc4dece38f950f7a37810dff3dab0 SHA-256: bdda87d4f0cfb797d0e6844d2b36dd45d3130fad32b3341a6545e091f2c51d18
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to compromised CMS upload directories or disposable hosting, indicating a link farm designed to redirect users. The ML classifier and ClamAV detection strongly suggest malicious intent, likely phishing or malware distribution. No scripts were extracted, and the document body was unreadable, but the heuristic firings and URL analysis are sufficient to determine the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://merlegdoktor.hu/tmp/20468014980.pdf In PDF document text
    • https://wurstfargo.com/wp-content/plugins/super-forms/uploads/php/files/11c9c030bae2f22c1fb0376628e16629/rarizemibinuduvemiku.pdfIn PDF document text
    • https://romalasergroup.com/userfiles/files/fopitibimafenirekab.pdfIn PDF document text
    • http://polimak.pl/userfiles/file/nufeforifurosa.pdfIn PDF document text
    • http://bizwd.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133b6f2ce5aa---63969118507.pdfIn PDF document text
    • https://congthuonghotel.vn/app/webroot/files/images/pages/files/18803601518.pdfIn PDF document text
    • http://safires.cz/ckfinder/userfiles/files/xetemipaxujug.pdfIn PDF document text
    • http://dalaichau.com/files/74742215394.pdfIn PDF document text
    • http://antropolog.ru/userfiles/file/jepunozazulodu.pdfIn PDF document text
    • http://romengo.com/ckfinder/userfiles/files/2585517712.pdfIn PDF document text
    • http://www.investing-in-women.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138cefca6820---16840571009.pdfIn PDF document text
    • http://njxinbell.com/upload/files/legawadisiwexe.pdfIn PDF document text
    • http://privateeducation.sg/verzsape/demo/upload/admin/files/pusiduzovuk.pdfIn PDF document text
    • http://extreamtuning.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613855a31cc50---24042242826.pdfIn PDF document text
    • http://cedule-plachty.cz/files/file/16446655023.pdfIn PDF document text
    • http://polyacer-ecp.com/userfiles/files/20210902_071345.pdfIn PDF document text
    • http://maivietnamesecotati.com/uploads/files/18496060213.pdfIn PDF document text
    • http://chelseafoodmart.com/uploads/files/rimoliv.pdfIn PDF document text
    • http://hanboo.cn/Uploads/file/2021090213573070554.pdfIn PDF document text
    • https://otoform.com/upload/ckfinder/files/25700617542.pdfIn PDF document text
    • https://mariellatriolo.it/public/file/melobapuvixefodowiw.pdfIn PDF document text
    • http://gammatradings.com/userfiles/file/popifupekugirifu.pdfIn PDF document text
    • http://salt17.com/userfiles/files/lerokotebilax.pdfIn PDF document text
    • http://eperon-kochersberg.com/img_db/4478242730.pdfIn PDF document text
    • http://wingmanresearch.com/userfiles/files/29317813044.pdfIn PDF document text
    • http://vuason.vn/upload/files/54435214569.pdfIn PDF document text
    • http://tootingtaxi.com/survey/userfiles/files/40469510758.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=wallpaper+mu+for+androidPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d089.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD089 10484 bytes
SHA-256: 5f3708da42f1769e5d11c4a11a74e79e14b503daa7c5504fee8e098b59283922
font_01_sfnt_off0000e83d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE83D 18424 bytes
SHA-256: 63154a2f141b9bb024e668c8f8a63f0dd7d881e864994d5fac5e2ac0536c2a20
font_02_sfnt_off0001186a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1186A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1