Malicious PDF — malware analysis report

Static analysis result for SHA-256 439a701eb24b9baa…

MALICIOUS

PDF

98.0 KB Created: 2021-09-17 18:28:47 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 18b2cd042410e6ceb2e6559bb2af16cd SHA-1: 9a718549d3b2a742f2d99cdf33c93d4e96b664dd SHA-256: 439a701eb24b9baa2c4d11b6bc28e987c35bf5c2fa66c95d3bc63652a1fdc028
236 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating it is a malicious phishing document, specifically designed to lure users into revealing recovery secrets or private keys. The document body is heavily obfuscated, but the presence of numerous external URLs, including those hosted on compromised CMS platforms and disposable domains, suggests an attempt to redirect users to malicious sites. The ClamAV detection and ML classifier further confirm its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 8

  • Recovery secret / private key request critical SE_SECRET_RECOVERY_LURE
    Document requests recovery phrases, private keys, backup codes, or saved passwords. Requests for these secrets in a document are high-risk.
  • 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.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • 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://krisoc.ru/uplcv?utm_term=add+gradle+to+android+studio
    • https://bellcera.60km.com/upload/files/jodupediwedesojunasotago.pdf
    • https://bahceneryaman.net/public/content-images/files/konoxoke.pdf
    • https://sudhirsachdevaclasses.com/ci/userfiles/files/zexuselavitadefaket.pdf
    • https://machnhaduong.com/images/uploads/files/99149066531.pdf
    • http://status-go.net/gfx/userfiles/files/xurowuzabakojik.pdf
    • http://usatovl.ru/upload/fckeditorfile/89805924237.pdf
    • https://veglifekc.org/wp-content/plugins/super-forms/uploads/php/files/13888315915.pdf
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1612f6285cf922---78942355897.pdf
    • https://dadrarad.ro/userfiles/file/66006537973.pdf
    • http://wisdomtours.net/upload/file/pemalanuzawitikuriranek.pdf
    • http://hosungtour.net/FileData/ckfinder/files/20210917_494E59F2C5A79426.pdf
    • http://studiolegalezullo.eu/userfiles/files/ketif.pdf
    • http://konditsionery-reutov.ru/upload_picture/file/86474469908.pdf
    • http://bisenzia.it/userfiles/files/91214815551.pdf
    • http://avvocatoandreabruschi.it/userfiles/files/40627736711.pdf
    • http://ettorebelfioreliutaio.it/userfiles/files/belezalisedozawodujuloz.pdf
    • https://rts-wm.com/ckfinder/userfiles/files/54773619063.pdf
    • http://es-hanasaki.com/yamituki-n/uploads/files/vegixamerusuzit.pdf
    • http://candleelectricals.com/uploaded_files/userfiles/files/dupomixoxurevazuxip.pdf
    • http://www.investing-in-women.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137ceffa79b6---43671283662.pdf
    • https://kimcert.org/E/file/55791858676.pdf
    • http://archgeo-leszno.pl/uploads/userfiles/files/98689658814.pdf
    • https://sbsoftware.ro/admin/userfiles/file/99241481076.pdf
    • http://arisutour.com/ckupload/files/kiwusazugopizasuw.pdf
    • https://santa.my/images/users/00000000/files/junapogetoxosola.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00011937.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11937 16792 bytes
font_01_sfnt_off0001314e.bin
ddd6c8bb41bbb6f5eda2b984a8230d1498b6c09691d66769fd898adbb2bc05c2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1314E 10504 bytes
font_02_sfnt_off0001491c.bin
cf45480b5714b2040260387b5b9243013b224f2645335479571187bb760730bc
pdf-font-stream PDF embedded font (sfnt) at offset 0x1491C 18324 bytes