Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81bdf72aec41962…

MALICIOUS

PDF

80.8 KB Created: 2021-03-31 22:50:49 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-23
MD5: fbab90be750252e65a4830f8e588e031 SHA-1: e4654626d3ae99af8f3360a715a1e31f1a388d9f SHA-256: c81bdf72aec419625a68cc46a1573ceea7455119444d237a60839534661b3891
134 Risk Score

Malware Insights

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

The PDF contains numerous links to external websites, many of which are hosted on disposable domains and appear to be part of a link farm. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The presence of a 'download' button heuristic further supports the lure of downloading a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 6

  • 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.
  • 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://leonvi.ru/award?keyword=biology+past+questions+pdf+download PDF link annotation
    • http://biweekamnf.com/60139198605f0tzr.pdfIn PDF document text
    • http://tupaxeguna.scienceontheweb.net/89407145844.pdfIn PDF document text
    • https://sibibogug.weebly.com/uploads/1/3/5/9/135990875/5476957.pdfIn PDF document text
    • http://good-production20.site/petrolia_isd_tx22oqp.pdfIn PDF document text
    • http://secureappeal.com/puzevigomenujobevaze6na5.pdfIn PDF document text
    • http://karnaval.host/wakogisabilibipavowoxjw10l.pdfIn PDF document text
    • http://dasiwujupuna.sportsontheweb.net/active_and_passive_voice_quiz_test.pdfIn PDF document text
    • http://rivepozepuxar.mywebcommunity.org/precalculus_with_limits_3e_chapter_7.pdfIn PDF document text
    • http://vixemifojetinag.sportsontheweb.net/jejolovagujasag.pdfIn PDF document text
    • https://suxugugufagiwa.weebly.com/uploads/1/3/4/7/134740592/nisadi.pdfIn PDF document text
    • http://kotudekudoges.getenjoyment.net/nsk_deep_groove_ball_bearing_catalogue.pdfIn PDF document text
    • http://springital.fun/susuzigareki0mbtu.pdfIn PDF document text
    • http://store50off.info/linen_sheet_set_kmart1c4bj.pdfIn PDF document text
    • https://jebasiju.weebly.com/uploads/1/3/1/3/131381450/regutilutow.pdfIn PDF document text
    • http://kedugobepuged.mywebcommunity.org/white_fang_of_the_leaf_kakashi.pdfIn PDF document text
    • https://famexowizesiz.weebly.com/uploads/1/3/4/3/134359716/0ad60ab3d5bdcb.pdfIn PDF document text
    • http://lixidepobejoji.mypressonline.com/pawipowokavofufofakol.pdfIn PDF document text
    • http://graatorama.space/what_is_the_hebrew_word_for_sons_of_god8q048.pdfIn PDF document text
    • https://milonotupilo.weebly.com/uploads/1/3/5/3/135347339/desasewosabafivokoso.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://uploads.strikinglycdn.com/files/735feab6-8fc3-41bd-ac47-db62f00100d0/lord_of_the_flies_study_notes.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d25f3cd9-44ff-47c9-a38b-653a6e77ca0c/letobabif.pdfIn PDF document text
    • http://lurarapekakaka.atwebpages.com/electronic_library_system.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/c583d2ec-6b8d-446a-986f-0fedb971926a/27547405779.pdfIn PDF document text
    • http://wowutuzineko.myartsonline.com/kusuzelozane.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6b3588a5-f35f-41e3-9a90-1eb4481830a8/meliderenijoz.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fa71.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA71 5484 bytes
SHA-256: c8f226d35a4a88e70a4e24e2d479a3c3b008f9d9a9e3b632f74caf5e41798d18
font_01_sfnt_off00010d4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D4E 11212 bytes
SHA-256: 34f2a5af822ea4817c345afeb71e083d472e7f51cbbb10cb36513a64e2ee6ef8