Malicious PDF — malware analysis report

Static analysis result for SHA-256 20b2c61b73ab5fb0…

MALICIOUS

PDF

67.6 KB Created: 2021-09-28 06:11:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 5984d3bfe8f7c17a719355d90dd3af1e SHA-1: 293fc70b81581a2e0a3ef2a7fe3a5d7609e3f8ad SHA-256: 20b2c61b73ab5fb06d0a26a9270a3afffa48b3aac1555ee06cc3ec8546f3ed2d
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF document is identified as malicious by ClamAV and an ML classifier, exhibiting characteristics of a phishing lure. It contains an image-only interface with a clickable link that redirects to algorithmically generated URLs hosted on disposable domains, a common tactic for distributing malicious content or harvesting credentials. The presence of multiple external URIs and the PDF_IMAGE_LURE heuristic strongly suggest a phishing or social engineering attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9957

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Image-only document with action trigger (screenshot lure) medium PDF_IMAGE_LURE
    PDF has 1 image(s), only 0 text block(s), carries a click-outward action, and is only 67 KB — typical shape of a phishing lure where a full-page screenshot hides a clickable button that launches or submits to an attacker URL.
  • 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://smidgel.ru/uplcv?utm_term=download+instaup+android PDF link annotation
    • https://cdmsig.com/ckfinder/userfiles/files/pajulakaxemuwowabupuzaz.pdfIn PDF document text
    • https://ecableapp.com/FCKeditor/FCKimgUpload/file/73700353756.pdfIn PDF document text
    • http://giaexploring.it/userfiles/files/jetuja.pdfIn PDF document text
    • https://seo-methodes.com/userfiles/file/17932784006.pdfIn PDF document text
    • https://daotaolaixesontay.com/uploads/file/xitolupulupupeziwog.pdfIn PDF document text
    • https://drrajanmahtani.com/userfiles/files/90673796124.pdfIn PDF document text
    • https://istruttorecinofilo.it/userfiles/file/12353094980.pdfIn PDF document text
    • http://df-2.de/images/daten/file/19348199186.pdfIn PDF document text
    • https://futuresbuilder.net/dayafter/uploadimages/newsimages/file/tofogupa.pdfIn PDF document text
    • http://receptlap.hu/files/55223523211.pdfIn PDF document text
    • https://www.etbsupplies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613d5fa5c052b---17428221801.pdfIn PDF document text
    • http://www.s4b.nl/upload/files/nerasud.pdfIn PDF document text
    • http://kibbkw.com/uploads/files/tunukixa.pdfIn PDF document text
    • http://midoriku.zaitakunet.jp/app/webroot/upload_images/files/88330366025.pdfIn PDF document text
    • http://www.sunarnuricomuisvealisverismerkezi.com/wp-content/plugins/super-forms/uploads/php/files/gbi4hrv78u6b0c0ebdgdr7p7a3/pelusukizutalolusavow.pdfIn PDF document text
    • http://kibunajcc.com/ckfinder/userfiles/files/54619226376.pdfIn PDF document text
    • http://www.psoevalledeabdalajis.es/ckfinder/userfiles/files/vezekowetuvamemefebogan.pdfIn PDF document text
    • http://studiopignotti.it/userfiles/files/bojavutawazu.pdfIn PDF document text
    • http://finance-bulldog.cz/UserFiles/File/wegapewowimasoderetelo.pdfIn PDF document text
    • http://ana-jsc.com/upload/files/84724257157.pdfIn PDF document text
    • https://colegiumaniucarei.ro/ckfinder/userfiles/files/78922889525.pdfIn PDF document text
    • https://magyar-logyogyasz.hu/fileok/file/noxulovunofirukupesi.pdfIn PDF document text
    • https://bfull.ru/uploads/files/jitokebagamososunefonib.pdfIn PDF document text
    • 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_off0000adbf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xADBF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c5d6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC5D6 10440 bytes
SHA-256: b9195960b1c50e2f0e8306ccaf4162f3927a0b95968ce955c23a15ff71f2d6f8
font_02_sfnt_off0000dd9e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD9E 14340 bytes
SHA-256: 7813f1e19b71491a4e85a74684100e18089e37cd0c25be8d781b3b619077b27a

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