Malicious PDF — malware analysis report

Static analysis result for SHA-256 d1b37815d2610b8d…

MALICIOUS

PDF

77.3 KB Created: 2021-03-29 14:12:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: ee2181437f63a40a021b37e4200b329f SHA-1: 21e191a9d896854aac312ec436e864c392011b1c SHA-256: d1b37815d2610b8d3d82cd56949aec57eeb04c6b5b667ae80893d7ff0e00e039
134 Risk Score

Malware Insights

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

The sample is identified as malicious by ClamAV and an ML classifier, with heuristics indicating it's a link farm on disposable hosting. The presence of a 'download button' heuristic and embedded URLs like 'https://jumiwimov.ru/123?utm_term=accepting+criticism+free+worksheet' suggests a phishing or malware distribution attempt. The document body, though heavily obfuscated, contains metadata related to 'wkhtmltopdf' and a date, but no clear textual lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9996

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
  • 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://jumiwimov.ru/123?utm_term=accepting+criticism+free+worksheet PDF link annotation
    • http://tarofolezebinu.iblogger.org/waboboruzolosonovajomogug.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4492240/normal_5ff7f4cb67827.pdfIn PDF document text
    • https://cdn.sqhk.co/jimumakevaji/dgeuWBC/psn_top_up_cards_uk.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4384036/normal_600cc054df1ef.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4418192/normal_600d1882d3ed5.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4408587/normal_6052dff9b6e03.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4413109/normal_5ffc9c55bf3ea.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4459785/normal_604d0d33a1c1f.pdfIn PDF document text
    • https://cdn.sqhk.co/gadujotev/ichdibR/new_email_template_outlook_2010.pdfIn PDF document text
    • http://fastgetme.online/dirt_devil_spot_scrubber_manual_espaolqlkfa.pdfIn PDF document text
    • http://show-visitor.xyz/juvizigelizofuwixepodmwiy2.pdfIn PDF document text
    • http://topsalon.xyz/how_to_use_a_wilton_104_tip4dahl.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4416659/normal_6043ff81039de.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4376866/normal_5fe70ecd5ced1.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4460457/normal_5fc59795a3176.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4459028/normal_5fe5c6957bda6.pdfIn PDF document text
    • http://pushbiz.fun/computer_programming_jobs_and_salary1550m.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://www.daltonmaag.com/In PDF document text
    • http://meguwuzib.rf.gd/meteletenamuzobejusoduxur.pdfIn PDF document text
    • http://xugonapo.rf.gd/los_angeles_chargers_uniform_schedule_2018.pdfIn PDF document text
    • https://s3.amazonaws.com/jiwotarotavuz/34492431714.pdfIn PDF document text
    • https://s3.amazonaws.com/pomaxa/vujowanaxemazi.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e46c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE46C 5120 bytes
SHA-256: c710df69f10179a10098a2006ff867eacc159b52ac3ddb2d99c3bfb021bac9f6
font_01_sfnt_off0000f5b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5B8 10444 bytes
SHA-256: 0ec6ca19b0da53e6692283a2e1d236eb459ed755346b68b3c8b8c571a0f527ad
font_02_sfnt_off00011977.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11977 4324 bytes
SHA-256: b50a2106bf82917db0cd3cf88f63c5e8cc3298b343ace5cffc591b35df33d24c