Malicious PDF — malware analysis report

Static analysis result for SHA-256 f804e3c3b2492931…

MALICIOUS

PDF

78.3 KB Created: 2021-09-18 12:35:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 0866144728532e4885bf7105754d783b SHA-1: 711f9f37eed1f71ff4d23d79622185c0edcc41b8 SHA-256: f804e3c3b24929311beea39bb3415e949205a070655fd3b56e62b0188cb9dfde
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample contains embedded JavaScript, which is a common technique for exploiting PDF vulnerabilities or initiating malicious actions. The presence of multiple external URIs, including those pointing to compromised CMS upload storage and disposable hosting, strongly suggests a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection further support its malicious nature, likely as a phishing or malware delivery mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://saigonservices.vn/images/uploads/files/sasujofomusip.pdf In PDF document text
    • http://morebricks.com/ckfinder/userfiles/files/xogowuvaliluzemukoma.pdfIn PDF document text
    • http://gt-outillages.fr/ressource/site-image/files/gimidupuzurilogozenagebo.pdfIn PDF document text
    • http://motopujcovnateplice.cz/userfiles/file/vevizikemaf.pdfIn PDF document text
    • http://papinchess.ru/userfiles/file/70830454911.pdfIn PDF document text
    • http://www.multigacos.com/admin/uploaded/fck/file/97717626313.pdfIn PDF document text
    • https://studiogreenwich.ru/wp-content/plugins/super-forms/uploads/php/files/d999fc5aea8574dc5614566e2f249477/2482323809.pdfIn PDF document text
    • http://sjar-tech.com/uploadfile/file///2021091802530830.pdfIn PDF document text
    • http://problemconsulting.com/img/download/files/77438675319.pdfIn PDF document text
    • https://bluetact.com/locktactyuma/userfiles/file/73743566054.pdfIn PDF document text
    • http://cetis156.neutronds.com/assets/js/ckfinder/userfiles/files/95784433381.pdfIn PDF document text
    • https://fajndoktor.cz/images/file/files/lagezitejuvigosivekenuv.pdfIn PDF document text
    • https://cfi-registration.amyhalter.com/buzzboxgift/img/userfiles/files/74074262414.pdfIn PDF document text
    • http://ramenhajimetustin.com/uploads/files/81026964381.pdfIn PDF document text
    • http://networkinglikepro.com/ckfinder/userfiles/files/mukaza.pdfIn PDF document text
    • http://obchodsezlatem.cz/upload/files/53963862398.pdfIn PDF document text
    • http://elistaprezentow.pl/userfiles/file/fikalomogadepigi.pdfIn PDF document text
    • https://bonekarusa.com/contents/files/87337755743.pdfIn PDF document text
    • https://guruamardaspublicschool.com/userfiles/files/24878524066.pdfIn PDF document text
    • http://104408017.linker.tw/files/37456055569.pdfIn PDF document text
    • https://staffxrecruitment.com/wp-content/plugins/super-forms/uploads/php/files/9332eb8eea1375c3e46b9356cac0895c/bosafum.pdfIn PDF document text
    • http://ljhalls.com/wp-content/plugins/super-forms/uploads/php/files/3bfd8bfba5ab43e6849635ff4b776f7e/2038569916.pdfIn PDF document text
    • http://benevolo.it/userfiles/files/70779885170.pdfIn PDF document text
    • http://kvarkeno56.ru/userfiles/file/rugeso.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=need+for+speed+most+wanted+obb+downloadPDF 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_off0000cec8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEC8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e6df.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE6DF 10768 bytes
SHA-256: 1cfceabc02c518f02dc3634429d89f3767305b0bec34e828d142ac964d5c9bc5
font_02_sfnt_off0000ff83.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFF83 16796 bytes
SHA-256: 986220ec2e0312aab97646ba7ee650f63b498ebb9dc6b0f36c2d5d20bc6393f4

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