Malicious PDF — malware analysis report

Static analysis result for SHA-256 f86f5a3dcbe01d62…

MALICIOUS

PDF

81.8 KB Created: 2021-09-21 15:31:38 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b6547ee6b7822f636c0fca530f902d86 SHA-1: 0a7f493e15ee6480b914f8fc9b7a5b5ae02d85ab SHA-256: f86f5a3dcbe01d6209c09d1bb72e36ec6c9304768b424080d7b2545c00c110d9
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a ML classifier and ClamAV, indicating it is likely a phishing or malware distribution lure. The file contains numerous external URIs and links to compromised CMS upload storage and disposable hosting, suggesting it functions as a link farm. The embedded content is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9977

Heuristics 6

  • 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 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://cructi.ru/uplcv?utm_term=pc+building+simulator+android+mod+apk PDF link annotation
    • https://successalpha.team/upload/files/74524385416.pdfIn PDF document text
    • https://cfacgroup.com/uploads/FCK_files/file/35527207555.pdfIn PDF document text
    • https://lacausedeslivres.com/userfiles/file/venuw.pdfIn PDF document text
    • https://sakitonus.ru/wp-content/plugins/super-forms/uploads/php/files/39c462679e6b1300ed693e20953bc564/nomigurolasumol.pdfIn PDF document text
    • http://cleangroupbd.com/ck/upload/files/nizopof.pdfIn PDF document text
    • https://eastmangroup.org/ckfinder/userfiles/files/dafupubejazovesuwova.pdfIn PDF document text
    • http://songhakbbq.com/uploads/files/romunevuxefima.pdfIn PDF document text
    • https://dentinale.eu/wp-content/plugins/super-forms/uploads/php/files/61fb3aaf740118a07de5e0f51b4eeafd/tejizaxurumafosanojid.pdfIn PDF document text
    • http://branpc.in/ckfinder/userfiles/files/16088266494.pdfIn PDF document text
    • http://www.ciesol.com/ckfinder/userfiles/files/55114989119.pdfIn PDF document text
    • http://kite-surf.sk/files/24450657736.pdfIn PDF document text
    • https://copacndg.com/images/uploads/files/wegelepamasexefuluninavo.pdfIn PDF document text
    • http://www.opencalgary.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613d75a945463---pilos.pdfIn PDF document text
    • http://fgosvo.ru/files/files/tuvatogubofinixane.pdfIn PDF document text
    • http://omeofest.eu/userfiles/files/zuruvemanidakenet.pdfIn PDF document text
    • http://xn--42-6kcdlkbomh7beggito5p.xn--p1ai/userfiles/file/venetogojoje.pdfIn PDF document text
    • https://etadelloro.it/images/file/19289706823.pdfIn PDF document text
    • http://www.icareonline.net.au/ckfinder/icare/files/gatepafakubisonajut.pdfIn PDF document text
    • http://verkoop-je-wagen.be/wp-content/plugins/formcraft/file-upload/server/content/files/16146b60e1f350---40947634335.pdfIn PDF document text
    • https://festivaldelmaridaje.com/sgi_userfiles/userfiles/files/81541536740.pdfIn PDF document text
    • http://ltptech.vn/uploads/userfiles/file/74042012685.pdfIn PDF document text
    • https://biroestarsa.hu/uploads/file/rawomogu.pdfIn PDF document text
    • http://ithalattagarantibelgesi.com/resimlerfiles/52187251182.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_off0000d9b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9B2 11056 bytes
SHA-256: 56e533955a5af4edfae21b70d34b51a4ce0313b380ad09d82548d14ca6ba5ff2
font_01_sfnt_off0000f2f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2F7 17684 bytes
SHA-256: c65d53f5d3041b09f59f1da296d7cd81a56b0347bd8d29fc3c2d897d1bc8b419
font_02_sfnt_off0001211f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1211F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1