Malicious PDF — malware analysis report

Static analysis result for SHA-256 efbbcadc1e8bcae1…

MALICIOUS

PDF

72.0 KB Created: 2021-08-29 17:10:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: dc8e7c296abeee78066fbd20153bc227 SHA-1: c17380bc2802ed9452c39c4e96127c3d279ae10d SHA-256: efbbcadc1e8bcae1da59130a345d1bfe0c3c86a3bdeb4d2b7f6fff96a4f9136b
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which point to compromised CMS upload storage or are part of a link farm on disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing or malware-hosting sites. The embedded JavaScript is likely used to facilitate these redirects or further obfuscate the malicious activity.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 7

  • 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.
  • 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://krisoc.ru/uplcv?utm_term=answers+to+math+problems
    • http://trubaopt.ru/content/file/salasovuveforigawebemexap.pdf
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/gmpviucd5ftv1v3nditv4h62s0/21702900.pdf
    • http://nacyc.jp/Upload/file/72573284502.pdf
    • http://tidomusica.com/uploads/files/202108260357064451.pdf
    • https://thejasmineway.net/wp-content/plugins/super-forms/uploads/php/files/s2da85ag2n7ir8s324li0g2htp/20466710271.pdf
    • http://tanabuauto.com/js/upload/files/dokuzenejifaduzajobekof.pdf
    • https://dptech.vn/uploads/files/vidozojunodi.pdf
    • https://gamaconsultores.cl/upload/file/34567297977.pdf
    • https://www.higher-energy-trampolineclub.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b4c5769a07a---sorifuboniduw.pdf
    • https://mercerapparelss.com/userfiles/files/8697739917.pdf
    • https://fellowpeo.com/wp-content/plugins/super-forms/uploads/php/files/df85004f76fc7430f9c581df65a23182/99652764376.pdf
    • http://sdds.be/userfiles/file/65971827274.pdf
    • http://worldnaturalfood.com/image/upload/File/15239393363.pdf
    • http://w3-japan.com/js/upload/files/25183468180.pdf
    • http://www.odnpoznan.pl/fotki/file/file/zemelobopobigid.pdf
    • http://dyglas.com/userData/board/file/nikuraxutawakoziterej.pdf
    • http://homeopathyhongkong.org/files/vazilororuladizetamotejo.pdf
    • http://99hospitalitygroup.com/ckfinder/userfiles/files/nubovezixawalunigujuxaga.pdf
    • https://luxurytravel-show.com/wp-content/plugins/super-forms/uploads/php/files/db149ede987a35e27b2876ee32189ecc/19371569639.pdf
    • http://imagespa.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160c943d77f9a6---fopalisaxar.pdf
    • https://study-go.info/wp-content/plugins/super-forms/uploads/php/files/cdd8e30c18b281bfa7b33bbe435cd80c/40435944852.pdf
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610895c19b029---nemivofubipedolevudir.pdf
    • https://gccpay.net/wp-content/plugins/super-forms/uploads/php/files/8aa180923a4f61af4502e902484ed915/sexasepoviked.pdf
    • https://m-astar.com/UserFiles/files/31406878434.pdf
    • https://rjiminfra.com/wp-content/plugins/super-forms/uploads/php/files/5122b51f4110d139c30333f5eebb0c05/52425523933.pdf
    • 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_off0000bbcf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xBBCF 16792 bytes
font_01_sfnt_off0000d3e1.bin
4efa3783f53f80961262c3629cc9633b1b8c1ab70bfd8b517d0aaf05da14e2be
pdf-font-stream PDF embedded font (sfnt) at offset 0xD3E1 15036 bytes
font_02_sfnt_off0000f9e2.bin
c7e395f9b0401b383ea50d2d00c997a9e6669120344ee160e3bd35abf925bf5a
pdf-font-stream PDF embedded font (sfnt) at offset 0xF9E2 10632 bytes