Malicious PDF — malware analysis report

Static analysis result for SHA-256 c8d5434ff67c91ba…

MALICIOUS

PDF

79.3 KB Created: 2021-09-12 01:42:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 12cab65bc1a653078aa6864bee8afb54 SHA-1: f165b4162ff4905dcaedf86db65ab4ffd7efe88c SHA-256: c8d5434ff67c91bab2888cb7e12be552af3804ef680637a190d428f1b726d52f
146 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file is identified as malicious by ML classifiers and ClamAV, with heuristics indicating it functions as a link farm on disposable hosting. The presence of numerous embedded URLs, many pointing to PDF files on various domains, suggests an attempt to distribute malicious content or conduct phishing. Although no scripts were explicitly extracted, the PDF structure and embedded links are indicative of a malicious document designed to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

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
  • 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 http://seatraderhk.com/userfiles/lowifivukoxax.pdf In PDF document text
    • https://ahl2005.com/ckfinder/userfiles/files/luweg.pdfIn PDF document text
    • http://aspbae.org/userfiles/file/fitikevavojelopuro.pdfIn PDF document text
    • http://ljjxmining.com/uploadfile/file///2021090315330921.pdfIn PDF document text
    • https://sakura-bashi.com/uploads/files/202109061401069557.pdfIn PDF document text
    • http://studioschicchi.eu/userfiles/files/dumejubidipuvemikovosopu.pdfIn PDF document text
    • https://slezanie.eu/userfiles/file/52419620081.pdfIn PDF document text
    • http://recit-de-vie.fr/userfiles/file/kafudodopemoko.pdfIn PDF document text
    • http://www.uc-kushiro.net/images/library/File/92927522831.pdfIn PDF document text
    • http://slsnn.ru/content/files/83668407047.pdfIn PDF document text
    • https://www.denisonlandscaping.com/wp-content/plugins/formcraft/file-upload/server/content/files/161330cfe4f31a---6733519043.pdfIn PDF document text
    • http://sz-nuoyi.com/Upload/file/2021091100452334948.pdfIn PDF document text
    • http://mashhadgardi724.ir/basefile/mashhadgardi724/files/36815045319.pdfIn PDF document text
    • https://tivicom.vn/upload/files/45379884955.pdfIn PDF document text
    • http://shopabrang.com/images/files/49457184067.pdfIn PDF document text
    • http://recrute.fr/files/files/nukilofuwafozidaje.pdfIn PDF document text
    • https://refakatci.net/userfiles/file/39905556846.pdfIn PDF document text
    • http://keacg.com/upload/files/pixusuketululupes.pdfIn PDF document text
    • http://www.brickchamber.com/ckfinder/userfiles/files/genutowa.pdfIn PDF document text
    • https://nhabe.com.vn/ckfinder/userfiles/files/74528049837.pdfIn PDF document text
    • http://commsoft.nu/demo/ktb/wsmbilder/files/fekezezisupugepa.pdfIn PDF document text
    • http://gimnazjum-krasiczyn.pl/img/userfiles/file/ditafatinotugefegigem.pdfIn PDF document text
    • http://etcpremium.com/userfiles/files/87672584473.pdfIn PDF document text
    • http://madiagranitosilano.it/userfiles/files/gifojutokusaz.pdfIn PDF document text
    • https://kirmatas.com/userfiles/file/96128346497.pdfIn PDF document text
    • http://datong-travel.tw/upload/ckeditor/files/20210910153444.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=narrative+of+the+life+of+frederick+douglass+full+text+pdfPDF 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_off0000d10e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD10E 11132 bytes
SHA-256: 7373588cfe895f2493ab8b34d82192559e0b6f9f94abe95c74ba70436b51758f
font_01_sfnt_off0000eb05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEB05 17176 bytes
SHA-256: bd8cf6c47b89ed140eb63d4f6b1e77437de22e528353bc67b4adea3ed6a5d682
font_02_sfnt_off000116d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116D8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1