Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f81bcc5fda8bd89…

MALICIOUS

PDF

81.1 KB Created: 2021-10-07 20:32:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: a825f7bdc384524882b9c6b18491a88c SHA-1: a5b12dddf794e5223ba489f06149a481a3f336a6 SHA-256: 4f81bcc5fda8bd894740fa32f7518fe7234b9134ab09c43d773df4c5237502e9
126 Risk Score

Malware Insights

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

The sample was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It contains numerous external URIs and is flagged as a link farm on disposable hosting, suggesting it's part of a phishing or malware distribution campaign. The PDF structure itself appears to be a lure, directing users to various external PDF files hosted on potentially compromised or malicious domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

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 https://osiindia.org/ckfinder/userfiles/files/40315135829.pdf In PDF document text
    • https://kabelkyaobuv.sk/editor_uploads/files/2567972027.pdfIn PDF document text
    • https://aristi-trap.com/upload/users/files/supovu.pdfIn PDF document text
    • https://smwebtechnology.com/arishayurveda.com/userfiles/file/pewuxawim.pdfIn PDF document text
    • http://wmasgroup.com/userfiles/file/gexeparogidazi.pdfIn PDF document text
    • http://fu-xin.tw/uploads/files/202109072333447412.pdfIn PDF document text
    • http://datavincity.com/uploads/ckfinder/files/wiwufinatogatok.pdfIn PDF document text
    • https://kimcert.com/E/file/4881292140.pdfIn PDF document text
    • https://flomogroup.com/upload/files/60162387147.pdfIn PDF document text
    • https://zoldlaptop.hu/ckfinder/userfiles/files/dimawiba.pdfIn PDF document text
    • https://o2opr.co/userfiles/files/bigavukiba.pdfIn PDF document text
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/pf5te4bsqh8tvh01df0n3ndpc7/kudoxavijiwalawose.pdfIn PDF document text
    • http://dossalas.com/wp-content/plugins/super-forms/uploads/php/files/d28b8246e5c1e2c8d1a84e5500f681b4/resimumuliwake.pdfIn PDF document text
    • https://ermolino.mebel18.com/uploads/files/60292104353.pdfIn PDF document text
    • http://www.novosib-sport.ru/ckfinder/userfiles/files/gupixisaripotebasevajin.pdfIn PDF document text
    • http://miraesusan.com/ckupload/files/72512781326.pdfIn PDF document text
    • https://eravikulamnationalpark.org/ckfinder/userfiles/files/bedoperegugorome.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210901_131949.pdfIn PDF document text
    • http://talani.nl/userfiles/image/file/xupagoduvepenuku.pdfIn PDF document text
    • http://senseoftourism.dk/userfiles/file/81822402952.pdfIn PDF document text
    • http://sfssolution.com/userfiles/file/73591662848.pdfIn PDF document text
    • http://vagtteam.dk/userfiles/Files/50978291825.pdfIn PDF document text
    • https://posaonakosovu.com/ckfinder/userfiles/files/29030577645.pdfIn PDF document text
    • http://gesundheit-im-blog.de/userfiles/file/58031581637.pdfIn PDF document text
    • http://sapthagireesyathra.srikarpagavinayagamills.com/userfiles/file/18172360633.pdfIn PDF document text
    • http://dailyxedayhang.com/userfiles/files/fanefebaxibutanonabofo.pdfIn PDF document text
    • https://cartolmania.it/file/77325414614.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=protection+bottle+witchcraftPDF 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_off0000d6ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD6AB 18716 bytes
SHA-256: dde2d8328a11affb6e30f7a9312365c67d57aeff757d4306c0b09c294fed437b
font_01_sfnt_off00010709.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10709 10492 bytes
SHA-256: 6f573bacd2ee4c342dab5c7fde4bfd5db6edc8ee5032707830873bd309f6df0c
font_02_sfnt_off00011edd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11EDD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1