Malicious PDF — malware analysis report

Static analysis result for SHA-256 3f762b86dc2bcab8…

MALICIOUS

PDF

89.5 KB Created: 2021-09-14 06:07:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 86d3e60105ca6ff3f9b09c45c8983f5c SHA-1: 37e2f480dcf9d2014c51c0b04ab032441d6e6393 SHA-256: 3f762b86dc2bcab80ff55b073122bbf2b83a2679d8e8f212dd8e5aefb134bdfd
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript and a large number of external URIs. Several heuristics indicate that these URIs point to compromised CMS uploads and disposable hosting, forming a link farm. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution by directing users to malicious content. The embedded JavaScript, while not fully analyzed, is a common vector for further exploitation in PDF documents.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9937

Heuristics 8

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • Urgency / deadline lure low SE_URGENCY_LURE
    Document contains urgency or deadline language ('account will be terminated', 'action required within 24 hours', etc.) — useful context, but low-signal without other findings
  • 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://www.kigimex.com.vn/ckfinder/userfiles/files/jinotivaxirojale.pdf
    • http://allegroescrow.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613297682b419---pezegixobatuwamuzevajago.pdf
    • http://de.ruben.pl/ckfinder/userfiles/files/8767391341.pdf
    • http://hadt.vn/upload/files/92467793978.pdf
    • http://bienchidan.org/uploads/files/13202727155.pdf
    • http://pantanalmsnews.com.br/ckfinder/userfiles/files/mukorabomewemofi.pdf
    • http://www.sushmitamukherjee.com/fckimages/file/44327070838.pdf
    • https://cakkue.com/contents/files/pevugegixosetun.pdf
    • https://samudra99.com/contents/files/gogojavopubijiberapumoje.pdf
    • http://air-con.ru/upload/files/gamekoxu.pdf
    • http://www.c-l-r-p.com/admin/ckfinder/userfiles/files/sopovatidovaduzevikaved.pdf
    • https://prcomponents.com/ckfinder/userfiles/files/pivunixubojudorin.pdf
    • https://dnmpaint.com/sdcc/images/file/mifobarabitinakefanep.pdf
    • http://impex-italia.it/userfiles/files/tinuboborexupuwuwamoti.pdf
    • https://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613527f416bf2---53660514748.pdf
    • http://regalmotors-jp.com/js/upload/files/73685975227.pdf
    • https://www.myjamaicais.com/wp-content/plugins/super-forms/uploads/php/files/d13b8f22825a05a83b8c6b12127d9885/87590324385.pdf
    • http://bangtaisay.com/uploads/userfiles/file/betatesojiza.pdf
    • https://www.bakkersvlaanderen.be/resources/plugins/ckfinder/userfiles/0/files/powusufosipifusi.pdf
    • http://ppogrimall.com/upload/editor_image/file/wubafidebonusudaj.pdf
    • https://habibitoursegypt.com/ckfinder/userfiles/files/56254587162.pdf
    • http://automyjka.pl/automyjka.pl/userfiles/file/73438047578.pdf
    • http://4998horo.gmmwireless.com/contents/files/gunagujap.pdf
    • https://www.lowdoc-loans.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161313d8bb053c---80962188083.pdf
    • https://halobysciton.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613259e718fb5---xofirawazogovifaxobujavi.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/fzgW7-mxBc0/uplcv?utm_term=strike+force+heroes+marvel
    • 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_off0000f879.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF879 16792 bytes
font_01_sfnt_off0001108b.bin
99b3bc7b56a01c720c191010dbbf1b20ecf1ffd3816a6c5bae3620b48f47222e
pdf-font-stream PDF embedded font (sfnt) at offset 0x1108B 18240 bytes
font_02_sfnt_off0001403b.bin
ef31a2ed46bdd9bb188e232df11c5bad3ae7bdc80fc9079d48e7bb74d2daea83
pdf-font-stream PDF embedded font (sfnt) at offset 0x1403B 10728 bytes