Malicious PDF — malware analysis report

Static analysis result for SHA-256 38cb03955c340d6d…

MALICIOUS

PDF

80.9 KB Created: 2021-10-09 21:12:56 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a8f8b4d6373545e4fc836c4cdb610fd7 SHA-1: c5b6cdbdae8dcf77fea1127e5703d5cd752dc7a3 SHA-256: 38cb03955c340d6def56496c382a4ff7dca80eac7b61cde3dd46b84e8160032f
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF file was flagged by ML classifiers and ClamAV as malicious. Heuristics indicate it functions as a link farm, with numerous URLs pointing to potentially compromised or disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links. The presence of multiple external URIs and a link farm structure strongly suggests an intent to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9985

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 https://coevent.ru/upload/files/tunevipuxuvexerudosexedow.pdf In PDF document text
    • http://thuocnam.xyz/images/files/24845012090.pdfIn PDF document text
    • http://filippodelvita.com/demo/userfiles/file/81280424304.pdfIn PDF document text
    • http://helloslow.com/data/userfiles/files/sinuj.pdfIn PDF document text
    • http://atlonnuri.org/UpLoadImage/editer/files/20793770428.pdfIn PDF document text
    • http://saltokisport.com/uploads/files/70015506103.pdfIn PDF document text
    • https://kodeac.com/wp-content/plugins/super-forms/uploads/php/files/uo4hcad1t1ujs2tgbq9hlb3lhr/65462397034.pdfIn PDF document text
    • http://boletin.alicantehosteleria.com/lib/ckfinder/userfiles/files/pufefe.pdfIn PDF document text
    • http://modelseafarm.com/kweb/ckfinder/userfiles/files/66304866986.pdfIn PDF document text
    • http://bularz-auto.pl/images/userfiles/file/49740749535.pdfIn PDF document text
    • http://mingmitrcoffee.com/user_img/files/rawuxufojapasugini.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614e6acabc3b0---9311025542.pdfIn PDF document text
    • https://jiu-hang.com/upfiles/editor/files/40720251308.pdfIn PDF document text
    • http://groupelamiri.com/uploads/FCK_files/file/19685039183.pdfIn PDF document text
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/6149ac22a53cbab5dd4c2bbbb929b365/kopolamatisag.pdfIn PDF document text
    • http://tjjjsh.com/uploads/files/dojapotojosujujunuwaso.pdfIn PDF document text
    • http://viettelhaiphong.me/data/dulieu/files/86113102475.pdfIn PDF document text
    • http://shengyaweb.com/uploadfile/file/2021100608454714.pdfIn PDF document text
    • https://nasco-ye.com/uploads/file/jizuxen.pdfIn PDF document text
    • http://7sate.com/filespath/files/20210919230443.pdfIn PDF document text
    • https://zakarpattya-tour.com/upload/xewuzup.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/LPIa9PGmDLg/uplcv?utm_term=interim+financial+reporting+ind+as+34PDF 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_off0000d4c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C9 18044 bytes
SHA-256: 2a3d30c5c5ce71cbb053b09597fa1d93627777929fd1021f02aca0e96a4abe6b
font_01_sfnt_off000103cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103CD 11164 bytes
SHA-256: a66fb62833dbbb1f061b07ee4dadac3dabae967ba6980dc618f7231a327b83c3
font_02_sfnt_off00011dc0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11DC0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1