Malicious PDF — malware analysis report

Static analysis result for SHA-256 8373985f64579c67…

MALICIOUS

PDF

83.7 KB Created: 2021-09-14 01:12:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 3b7739431a8effd9701091d1237301b1 SHA-1: b578999df54dc80ac9dc71e3484d4ac31f496acb SHA-256: 8373985f64579c678fae6ee755a4837d1852a6ea70d56b2d214c8562be323f03
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to external PDF files hosted on domains flagged as potentially compromised or disposable. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or distributing further malware. The structure suggests a link farm designed to obscure the ultimate destination and leverage potentially compromised web infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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
  • 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.
  • 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://studiofelician.com/userfiles/files/71109264330.pdf In PDF document text
    • https://pima-alarms.eu/slicice/file/17938067356.pdfIn PDF document text
    • http://menifee.hanasushichoice.com/uploads/files/gowujenu.pdfIn PDF document text
    • http://storemisr.com/uploads/files/35075702401.pdfIn PDF document text
    • http://fszhenjia.com/upfolder/e/files/20210904123258.pdfIn PDF document text
    • http://griesvoegwerken.nl/UserFiles/file/92168464714.pdfIn PDF document text
    • http://werder-ritter.de/UserFiles/File/bubisawakufafijulu.pdfIn PDF document text
    • http://mansiya.com/uploadfile/files/57562508726.pdfIn PDF document text
    • http://luchetti.it/userfiles/files/20572539656.pdfIn PDF document text
    • http://studiocommercialedelpiano.it/userfiles/files/fewudusitoga.pdfIn PDF document text
    • http://xn--80aaaaadfwa5aftjhxrkcrg8iwc.xn--p1ai/pict/file/90527985575.pdfIn PDF document text
    • http://bebelino.ru/userfiles/file/88453097817.pdfIn PDF document text
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/03d31471278deed60c8f3d89ca2cbad9/38197275495.pdfIn PDF document text
    • https://homeaestheticsllc.com/wp-content/plugins/super-forms/uploads/php/files/d6c5494fab71fbfa87cbf85e2b27a704/tedenevune.pdfIn PDF document text
    • http://puginternational.com/ckfinder/userfiles/files/15509118177.pdfIn PDF document text
    • http://www.yeosung21.or.kr/ckfinder/userfiles/files/1631193085.pdfIn PDF document text
    • https://hanoihome.net/img_duhoc/files/sigomubuzujifupaxod.pdfIn PDF document text
    • https://vhcvietnam.vn/ckeditor/images/files/pugepuj.pdfIn PDF document text
    • http://vetsnab32.ru/userfiles/file/wepefakitopuxak.pdfIn PDF document text
    • http://fotosvatba.net/userfiles/file/36154049822.pdfIn PDF document text
    • http://erainbowrealty.com/userfiles/file/xazuzudaxinima.pdfIn PDF document text
    • https://www.cdsale.org.au/application/third_party/ckfinder/userfiles/files/worojujuze.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613f36eec73ee---38852402009.pdfIn PDF document text
    • http://hissekurban.com/resimler/files/74463037488.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=surface+go+2+versus+ipadPDF 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_off0000e275.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE275 17576 bytes
SHA-256: d1e5f61f9d3b16c95710d348ed000c5042c0f5458f4516de09b3f8eb1f6dd69d
font_01_sfnt_off00011010.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11010 10908 bytes
SHA-256: 27bc77beff13da941d8d8e06657a604f2745a5740b6ae245329b47ce76486792
font_02_sfnt_off0001294d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1294D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1