Malicious PDF — malware analysis report

Static analysis result for SHA-256 28557aa3c5edd533…

MALICIOUS

PDF

81.0 KB Created: 2021-09-16 08:03:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: c96c408f58141bab48f3c809a034ef62 SHA-1: b4ee708cae391e1f334dd2e3511c8a7aab47271d SHA-256: 28557aa3c5edd533747967e390b06f81d53b0e10926dde26cbf855f5782928be
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by a machine learning classifier and ClamAV as malicious, with a high-confidence detection of Pdf.Phishing.Trojan. The presence of numerous embedded URLs and a heuristic indicating a link farm on disposable hosting strongly suggests a phishing or malware distribution attempt. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further supporting the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

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 http://tidomusica.com/uploads/files/202109100915569470.pdf In PDF document text
    • https://glaze-metalart.com/upload/files/38373310452.pdfIn PDF document text
    • https://leavereview.com/customerinterview/ckfinder/userfiles/files/mavupukebigi.pdfIn PDF document text
    • http://dilimkebab.com/userfiles/file/44295906242.pdfIn PDF document text
    • http://geyuping.com/geyuping/uploadfile/file/2021090618202373499.pdfIn PDF document text
    • http://hbtsap.com/Upfiles/news/file///52562379422.pdfIn PDF document text
    • https://windsbs.biz/files/file/falaxudomomigumedofit.pdfIn PDF document text
    • https://viceda.com/userfiles/file/17665356784.pdfIn PDF document text
    • https://hamzsabegi60szallo.hu/UserFiles/File/titafavelimatalomavunoz.pdfIn PDF document text
    • https://institutdesante.org/userfiles/file/32679764053.pdfIn PDF document text
    • http://huanghels.com/filespath/files/20210907115526.pdfIn PDF document text
    • http://busto-wl.gattinonimondodivacanze.it/themes/userfiles/files/64568460718.pdfIn PDF document text
    • http://ryanoomen.nl/uploadimages/files/pobokepisap.pdfIn PDF document text
    • https://www.highettmetal.com.au/application/third_party/ckfinder/userfiles/files/71730802698.pdfIn PDF document text
    • https://avistravel.ro/userfiles/file/tubodafevugesabudodoril.pdfIn PDF document text
    • http://artdealer.vn/upload/fckimagesfile/b295d09e7e5fd6c496627233460bd52e.pdfIn PDF document text
    • http://sissonne.hu/editor_up/55136519322.pdfIn PDF document text
    • http://f-okinawa.com/img/tmp/file/gotuxenasutotepewepajos.pdfIn PDF document text
    • http://english-island.pl/wp-content/plugins/super-forms/uploads/php/files/dfa53ig0c7nc2gnedhffucdsg4/vuwitipenewuvediguwotupaz.pdfIn PDF document text
    • http://e-photo.lv/ckfinder/userfiles/files/86628634014.pdfIn PDF document text
    • http://growlink.biz/userfiles/file/17648888710.pdfIn PDF document text
    • https://dewalt-naradi.cz/media/upload/editor/file/82346038583.pdfIn PDF document text
    • http://chanhbon.vn/media/ftp/file/42828533286.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=i+am+happy+synonymPDF 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_off0000d92f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD92F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f146.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF146 10112 bytes
SHA-256: a260c54685bcf5a507806e4ea206a464b3a64fb3323ced824012f0a1fac91535
font_02_sfnt_off000107a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107A2 17840 bytes
SHA-256: db71a956a841ed533d3ce0a1e69d6970c05054d751e2dcdee4cffcbd8f320a77