Malicious PDF — malware analysis report

Static analysis result for SHA-256 83cc7864a44b9f1c…

MALICIOUS

PDF

77.1 KB Created: 2021-09-18 09:07:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 0f39dbc36d03b7a4ee51b986e4c2e018 SHA-1: 27100e1ab64d0b975ab72afe018f87788d6b541a SHA-256: 83cc7864a44b9f1c15814af8b0656eb8639fc5e4835a3d67555cab01c113fa8f
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a high-confidence ML classifier and ClamAV detection, indicating malicious intent. The presence of numerous embedded links, many pointing to unknown or potentially malicious domains, suggests a phishing or malware distribution campaign. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic specifically highlights the use of link farms on disposable hosting, reinforcing the malicious nature of the document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 5

  • 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.
  • 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 http://nebovsem.ru/app/webroot/files/files/44747761957.pdf In PDF document text
    • https://sf-tfi-pgu.uz/wp-content/plugins/super-forms/uploads/php/files/c05523303563469331d61a9cb9ff0037/kuvejezoripigogizumi.pdfIn PDF document text
    • http://www.parinet.fi/tiedostot/files/14738709402.pdfIn PDF document text
    • http://mn-print.ru/ckfinder/userfiles/files/taderuvalixas.pdfIn PDF document text
    • http://realcomfort.ru/content/upload/file/10137127982.pdfIn PDF document text
    • https://godahoian.com/app/webroot/upload/files/38356789052.pdfIn PDF document text
    • http://turatabor.hu/media/girapag.pdfIn PDF document text
    • http://colantuono.it/userfiles/files/vumixotuvimigesesodikepu.pdfIn PDF document text
    • http://drthchowdary.net/userfiles/file/46025638523.pdfIn PDF document text
    • https://weddingitaly.jp/images/file/goforedozes.pdfIn PDF document text
    • https://ajambary.com/userfiles/file/vulemukuzatalubililisafal.pdfIn PDF document text
    • https://pavillonwohlen.ch/userfiles/files/93077295314.pdfIn PDF document text
    • http://agriturismolataggiasca.eu/userfiles/files/31392929367.pdfIn PDF document text
    • http://texinpack.com/uploadfile/file///2021090516233219.pdfIn PDF document text
    • https://eastmangroupllc.net/ckfinder/userfiles/files/79350188916.pdfIn PDF document text
    • http://opt-russtd.ru/data_center/upload_pictures/file/20838110354.pdfIn PDF document text
    • https://dnsbp.com/all4help/fckuserfiles/file/5479829977.pdfIn PDF document text
    • https://lesura.net/userfiles/file/37591763097.pdfIn PDF document text
    • https://liho.cz/UserFiles/File/fesiwotonosi.pdfIn PDF document text
    • http://njchemland.com/upload/files/59081032400.pdfIn PDF document text
    • http://villaturri.it/wp-content/plugins/formcraft/file-upload/server/content/files/16136e78f0c533---6061978281.pdfIn PDF document text
    • http://tindangnhadat.vn/upload/files/sakirinasovefakizojene.pdfIn PDF document text
    • http://eia-edu.com/userfiles/file/81148229093.pdfIn PDF document text
    • https://poolpoint.be/uploads/file/xadiv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=file+harvest+moon+ppssppPDF 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_off0000c857.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC857 18016 bytes
SHA-256: 76664c6f06860c151c1338c978f577ec90c0225324660e784a07afb577cf4953
font_01_sfnt_off0000f72d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF72D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010f44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F44 10560 bytes
SHA-256: 82b8cf3d586f3c64e9e1687927411a2d629e7493e1401a07087470a422d96ced