Malicious PDF — malware analysis report

Static analysis result for SHA-256 81b398df3206dc81…

MALICIOUS

PDF

81.1 KB Created: 2021-09-12 12:56:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: d17ff9ec476410731fd82daaf453279a SHA-1: 9b6b6e0ec99db2807702e9cc24a2c165625b89c6 SHA-256: 81b398df3206dc8165e739a58fa2acdb16de3efefa4fee89eb333fdf5a5b969c
156 Risk Score

Malware Insights

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

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external links, many pointing to compromised CMS uploads or disposable hosting, suggesting a link farm designed to redirect users. The presence of 'utm_term' parameters in some URLs further supports a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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://pistant.ru/uplcv?utm_term=yubo+premium+free+apk PDF link annotation
    • http://zaiger.ru/img/file/kumeragutevozanagipebaku.pdfIn PDF document text
    • http://livestreaming.group/wp-content/plugins/super-forms/uploads/php/files/bqsa9s09bp1midbroajjo9dti4d6g25i/xebeletil.pdfIn PDF document text
    • https://sapporopools.com/contents/files/lepalolitasu.pdfIn PDF document text
    • http://precedent.by/_newsite/images_from_html_editor/file/21899546833.pdfIn PDF document text
    • http://purepoem.com/resource/docContentImg/file/2021-09-12/4ea20b2e7fd11d7ae029cb1558cd89c7.pdfIn PDF document text
    • https://cicadit.ro/UserFiles/file/bosepefozodiroliw.pdfIn PDF document text
    • https://benqmusicworkshop.com/fupload/file/vedanujosizasixapetotav.pdfIn PDF document text
    • http://ieltsadd.ir/cache/fck_files/file/zutorag.pdfIn PDF document text
    • http://adria-ex.com/images/blog/file/55922053784.pdfIn PDF document text
    • https://bor-diing.com/upload/files/89615153727.pdfIn PDF document text
    • https://partnermind.cz/images/files/87557095956.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/nifobuzojotitepupu.pdfIn PDF document text
    • https://coherence.cz/userfiles/file/15887503505.pdfIn PDF document text
    • https://www.baust.edu.bd/app/webroot/ckfinder/userfiles/files/40622737160.pdfIn PDF document text
    • http://bouwbedrijfansing.nl/userfiles/file/ropebekuwup.pdfIn PDF document text
    • http://sro52.ru/uploads/files/70584378831.pdfIn PDF document text
    • http://panyuchen.com/ckfinder/userfiles/site_eachfun_com/files/64936083563.pdfIn PDF document text
    • http://chengzechem.com/upload/files/wudozad.pdfIn PDF document text
    • https://ateneoarbonaida.com/wp-content/plugins/formcraft/file-upload/server/content/files/161390fa09e1ff---zedobet.pdfIn PDF document text
    • http://files.ibiza-ferien.de/file/nirexesubajumasudewop.pdfIn PDF document text
    • http://geo-equipe.it/userfiles/files/14819925370.pdfIn PDF document text
    • http://yongchengtech.com/uploads/files/202109041403061582.pdfIn PDF document text
    • https://www.temsilcisitesi.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132eefe27323---jinujiberituregida.pdfIn PDF document text
    • https://smwebtechnology.com/arishayurveda.com/userfiles/file/79590320915.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_off0000d821.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD821 10420 bytes
SHA-256: 88d6790db0311e8cdbbd043a2d17480857e9f07311ffbf61f3de95f79a637cc1
font_01_sfnt_off0000ef7b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEF7B 18256 bytes
SHA-256: e6331df1231c6adfbb520ff040d434117dd1aa86a775d424188c1e31caa65ec2
font_02_sfnt_off00011ec4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EC4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1