Malicious PDF — malware analysis report

Static analysis result for SHA-256 161133af8ff848ff…

MALICIOUS

PDF

69.8 KB Created: 2021-09-18 05:35:53 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: f7721da4325937389a728fd73b3e216d SHA-1: 51f1807f2a0077fc3fb3cd15efab5131a3f2ac6e SHA-256: 161133af8ff848ffab2109fa6b801700fc7c2b7ac0fb78d5d52eec8050104546
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple external links, with one heuristic identifying it as a link farm on disposable hosting. The ClamAV detection and ML classifier strongly indicate malicious intent. While no scripts were explicitly extracted, the presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics suggests the PDF is designed to redirect users to potentially harmful sites, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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 https://krisoc.ru/uplcv?utm_term=how+to+block+a+cell+phone+call PDF link annotation
    • https://pnp-studio.com/fckeditorfiles/file/bisepiwu.pdfIn PDF document text
    • http://ambulatorioveterinariobubiniregini.eu/userfiles/files/naxitopenas.pdfIn PDF document text
    • http://goldendoodlesofthesierranevadas.com/userfiles/file/xozilojuwevimedemedek.pdfIn PDF document text
    • http://centronegozi.com/public/9571597725.pdfIn PDF document text
    • https://quangcaowebsite.vn/uploads/files/niduzaxotetigafuzawasizod.pdfIn PDF document text
    • http://emanuelmlevin.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/lirowej.pdfIn PDF document text
    • http://stphilomenaonline.org/userfiles/file/55697151655.pdfIn PDF document text
    • https://beyondpins.com/calisma2/files/uploads/23122325671.pdfIn PDF document text
    • http://sieuthibds.net/images/files/61046826526.pdfIn PDF document text
    • http://fteq.ru/files/file/89841245265.pdfIn PDF document text
    • http://aktifbant.com/resimler/files/tovizudopulo.pdfIn PDF document text
    • http://orbitsecurity.qa/pro_mvp_tech/uploads/file/sigasuzulaxixexakis.pdfIn PDF document text
    • http://dietmoiquangle.com/webroot/img/files/gomefotujalebilo.pdfIn PDF document text
    • http://p-itos.net/admin/userfile/image/file/31103241440.pdfIn PDF document text
    • http://megat.pl/uploaded/fck_files/file/fovitor.pdfIn PDF document text
    • http://tokyo-sanritsu.com/userfiles/file/56219862008.pdfIn PDF document text
    • http://snookerfootball.eu/wp-content/plugins/formcraft/file-upload/server/content/files/161375ba2ab90e---jejejorupiwimi.pdfIn PDF document text
    • https://www.ideakliniksisli.com/wp-content/plugins/formcraft/file-upload/server/content/files/161452e1aa9e4c---28486840926.pdfIn PDF document text
    • http://congtyvima.com/images/Download/daxeleg.pdfIn PDF document text
    • http://suvagcentr.ru/userfiles/files/80198648968.pdfIn PDF document text
    • http://ellenia3.eu/userfiles/files/miloma.pdfIn PDF document text
    • http://sial.pl/galeria/file/70156265949.pdfIn PDF document text
    • 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_off0000b3ad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB3AD 15076 bytes
SHA-256: e42986ed9dbef311ced0278882f3e2a25b47b0f50082a00d6c6ed5a873d54ab3
font_01_sfnt_off0000d9e3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9E3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f1fa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF1FA 10420 bytes
SHA-256: 9c4548431617a5e517cf391a0bf83782a03509947723a296f3a04582c84d7a44