Malicious PDF — malware analysis report

Static analysis result for SHA-256 439b488e49c155bd…

MALICIOUS

PDF

80.6 KB Created: 2021-09-14 15:04:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 9c5adb563e70088ed2bc6ed8f51954d3 SHA-1: 17d1887817e9ccc3b79f37910bc7d64b69a689a3 SHA-256: 439b488e49c155bdec59d3131969ed56cdaab90f38b1d221661e3eaf63c5b3a6
142 Risk Score

Malware Insights

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

The PDF contains embedded JavaScript and numerous external links, many of which are hosted on disposable domains, suggesting an attempt to distribute malicious content or phish users. The presence of a 'download button' heuristic further supports a lure-based attack pattern. ClamAV detection as 'Pdf.Phishing.Trojan' confirms the malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://synerhu.ru/uplcv?utm_term=gta+sa+apk+obb+file PDF link annotation
    • http://sklenicky-obchod.cz/web/admin/fckeditor/userfiles/file/tutidumatodikaxovadakagu.pdfIn PDF document text
    • https://ce-mi.pl/uploads/userfiles/files/58872828974.pdfIn PDF document text
    • http://mentor-tutor.com/newGroserLikeProject/uploads/files/seleviritamukopatibup.pdfIn PDF document text
    • https://airbays.com/userfiles/file/85866914586.pdfIn PDF document text
    • http://www.leesii.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613838c289305---12364660638.pdfIn PDF document text
    • http://cachnhietwin.com/luutru/files/lomuwenogosotipesowal.pdfIn PDF document text
    • http://isystemlab.com/admin/ckfinder/userfiles/files/63649379809.pdfIn PDF document text
    • https://himalmanpower.com/ckfinder/userfiles/files/53442248627.pdfIn PDF document text
    • https://braintreeclinics.com/app/webroot/img/files/joropigajodepapofujulewas.pdfIn PDF document text
    • https://responsible-tourism-alliance.com/content_file/files/gafawirebixarapedudaj.pdfIn PDF document text
    • http://sspvjd.com/FileData/ckfinder/files/20210908_30DA12B7BD58F675.pdfIn PDF document text
    • https://www.l-games.jp/js/ckfinder/userfiles/files/83676239204.pdfIn PDF document text
    • http://hanstime.com/userData/board/file/7748258525.pdfIn PDF document text
    • https://graphicart.ro/fckfiles/file/karokivevepaguzofowuwi.pdfIn PDF document text
    • http://mtreurope.com/ckfinder/userfiles/files/97763897150.pdfIn PDF document text
    • http://xn--80aer5aza.xn---42-5cdakyymnnb9ake1az.xn--p1ai/ckfinder/userfiles/files/30192323895.pdfIn PDF document text
    • https://pre-www.bridge-college.com/uploaded/ckeditor/files/95246235621.pdfIn PDF document text
    • https://tectrongim.com/uploads/file/21522199054.pdfIn PDF document text
    • http://boatmonies.com/uploads/files/2264460910.pdfIn PDF document text
    • http://bmcnx.com/userfiles/file/beropelom.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/2021911637416002.pdfIn PDF document text
    • https://maritime-models.com/userfiles/file/17574397419.pdfIn PDF document text
    • https://htcpost.vn/vietpost.vn/img_content/file/22593235368.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_off0000da23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA23 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f23a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF23A 10420 bytes
SHA-256: 387fd0ab7e73537c38e8270a7d6b90fd5c64cab3da6a6c340744f5099293b973
font_02_sfnt_off000109c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109C9 16584 bytes
SHA-256: 990e812c1b70f18829dab372b2dd878c91e969681d8edcb6d6d8dd3ec359b4e4