Malicious PDF — malware analysis report

Static analysis result for SHA-256 aa99903de1d066dc…

MALICIOUS

PDF

70.8 KB Created: 2021-09-24 17:55:14 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b75a8b6c9e618a18313a7141045b2a6e SHA-1: c7b72ca5e93a9437df8dbd9280fcc7dcaf526858 SHA-256: aa99903de1d066dce8175b0728ff7eb0c429c5c5358e0091a3b37efc1c251b51
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains a large number of embedded URLs, many of which point to compromised websites and disposable hosting, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent. Although no scripts were explicitly extracted, the nature of the embedded links and the heuristic firings point towards a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 https://udachi.co.th/wp-content/plugins/super-forms/uploads/php/files/qruo44gu82flp6aguj0onfhb8f/46343689533.pdf
    • https://szabobuszberles.hu/files/files/49409480143.pdf
    • https://www.thecandystoresudbury.com/wp-content/plugins/super-forms/uploads/php/files/4g0da9gmu2r07rpfdjrbmkkrnn/61811683779.pdf
    • http://esistore.lu/userfiles/file/viwowafoni.pdf
    • http://www.fattyweng.com.sg/wp-content/plugins/formcraft/file-upload/server/content/files/16136e8874f954---84517660028.pdf
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/k1nteciuqedqv9ocnq8h2ta9h0/22266825192.pdf
    • http://findusafranchise.com/files/files/guramagotazulo.pdf
    • https://sodigital.it/wp-content/plugins/formcraft/file-upload/server/content/files/1613f36367043e---11528768568.pdf
    • https://sikdercollegeofpharmacy.com/scp/ckfinder/uploads/userfiles/files/25349672435.pdf
    • https://f27szerviz.hu/upload/files/61567744304.pdf
    • http://nhasachthunam.com/upload/files/63925561125.pdf
    • http://uniquehotelsolutions.com/files/others/71654373103.pdf
    • https://stpetejazz.com/wp-content/plugins/super-forms/uploads/php/files/2qf4f9eocc7tto26c1ltm74gtb/32017714209.pdf
    • http://imosa.asia/uploads/files/202109141437559239.pdf
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/16138de23f33ed---buzurixo.pdf
    • http://gzky.cn/dubeite/ckfinder/userfiles/files/20210903_221730.pdf
    • http://sahamit.net/userfiles/file/dirovijukot.pdf
    • https://sakesushimn.com/userfiles/files/42075553049.pdf
    • http://saxonrt.hu/img/userfiles/files/vumibunusulegajekofawe.pdf
    • http://aotwresort.org/ckfinder/userfiles/files/fakozeziraluka.pdf
    • https://ubitanduk.com/contents/files/gozivew.pdf
    • http://biosystech.com/pdsFck/file/rilapejiki.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=psiphon+pro+unlimited+data
    • 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_off0000b298.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xB298 16792 bytes
font_01_sfnt_off0000caaf.bin
1c812dc10bc2685bcbfc0b8b2ef3ccbdc0554953a550e55ce55c9db1d40849f1
pdf-font-stream PDF embedded font (sfnt) at offset 0xCAAF 10756 bytes
font_02_sfnt_off0000e331.bin
d411d9bbe4be28a084d0bd8f9d505e5defcc640b456c27bddc594a68c7b9a022
pdf-font-stream PDF embedded font (sfnt) at offset 0xE331 16468 bytes