Malicious PDF — malware analysis report

Static analysis result for SHA-256 f71d1fac1e937435…

MALICIOUS

PDF

80.3 KB Created: 2021-09-17 02:38:11 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 50cbf370155e770d5c88b9d6e005bb80 SHA-1: 7e05779f417d0b8185cb973649b5b1b63eb275ed SHA-256: f71d1fac1e9374353fd59b719e0e98fa628f902afd9de9fd9ad68df824b2a88a
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document contains numerous links to external PDF files hosted on various domains, many of which are identified as disposable hosting. The heuristic 'PDF_RANDOM_URL_LINK' and 'PDF_SEO_DISPOSABLE_LINK_FARM' indicate a pattern of distributing malicious content through a link farm. The ClamAV detection and ML classifier further support the malicious nature of the file, likely serving as a lure to download further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://corising.info/sa_upload/userfiles/file/20210909031519.pdf In PDF document text
    • http://abwbaltimore.com/uploads/files/59049194654.pdfIn PDF document text
    • https://simplehome.ro/ckfinder/userfiles/files/divafulinewuwej.pdfIn PDF document text
    • http://jr.ac.th/ckfinder/userfiles/files/113561752.pdfIn PDF document text
    • http://tianlanip.com/filespath/files/20210913051420.pdfIn PDF document text
    • https://alev.az/userfiles/file/voragegamenolufuberujal.pdfIn PDF document text
    • https://kvzriu.org/images/file/dudikasinudidazibufidegeg.pdfIn PDF document text
    • http://andersonlawdecorah.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/77482406275.pdfIn PDF document text
    • http://abarappresentanze.it/userfiles/files/34375172084.pdfIn PDF document text
    • http://veterinarioassociatopacinidallatorre.eu/userfiles/files/77876439731.pdfIn PDF document text
    • http://lctrading-gmbh.com/ckfinder/userfiles/files/9746985145.pdfIn PDF document text
    • http://zimmerei-possert.at/dudivesovesaf.pdfIn PDF document text
    • https://lideregitimpaketleri.com/calisma2/files/uploads/timefomofitanazukigozeg.pdfIn PDF document text
    • https://0922.sproname.com/files/userfiles/files/kuxubogukedobufalub.pdfIn PDF document text
    • http://sacoorhealth.pt/site/upload/file/14777706681.pdfIn PDF document text
    • http://geasit.it/userfiles/files/gaferimariwebelo.pdfIn PDF document text
    • http://svarovani-tig.cz/userfiles/file/95391673500.pdfIn PDF document text
    • http://jpind.pl/userfiles/file/vukiwoxawi.pdfIn PDF document text
    • http://unitec-egypt.net/userfiles/file/sosikowiwikewujoveduwatok.pdfIn PDF document text
    • http://elektrostroy.kz/ckfinder/userfiles/files/fojidaw.pdfIn PDF document text
    • http://tries.cz/media/images/upload/file/rofipuzixewexo.pdfIn PDF document text
    • http://www.sandipmallick.com/fckimages/file/76551965181.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1xuhb7AK25c/uplcv?utm_term=runescape+mobile+androidPDF 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_off0000d532.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD532 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000ed44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED44 17652 bytes
SHA-256: c8334ccdd1ac2b3f24048798d981e5c93b06994795311d66f422a66f85fba4a6
font_02_sfnt_off00011aff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AFF 10860 bytes
SHA-256: c6af2a09adf31ba22375cf685b52c05aaf0aa06394a906da9cd0b75abe4e5b1d