Malicious PDF — malware analysis report

Static analysis result for SHA-256 c844b0c781093eaa…

MALICIOUS

PDF

94.2 KB Created: 2021-06-11 17:25:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-20
MD5: d6006d5b75b033acf50afab99e50ff21 SHA-1: 73e58c55b02d10fc98c935f8ea9b593e2a704beb SHA-256: c844b0c781093eaa24056b6d28c652646dfed13aa10d381627147374c9f72d62
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a link farm pointing to numerous compromised WordPress sites, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be junk data, but the presence of external URIs and the overall structure point towards a malicious link distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9997

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://allytemp.ru/uplcv?utm_term=mxq+4k+rk3229+firmware+android+7.1+2 PDF link annotation
    • https://www.chortho.co.uk/wp-content/plugins/super-forms/uploads/php/files/kqddpffaaqshqngfcp5dahvvv7/41759541541.pdfIn PDF document text
    • http://morethancars.nl/uploads/edytor/file/betikewodikuf.pdfIn PDF document text
    • http://bochosushi.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a27993186cc---fasurusetajelefev.pdfIn PDF document text
    • https://www.lipfish.no/wp-content/plugins/formcraft/file-upload/server/content/files/16075dea4db1c1---dujajotixawidisesirid.pdfIn PDF document text
    • https://www.chinacimctrailer.com/wp-content/plugins/super-forms/uploads/php/files/18f78ee5f7dcdf60d8b8b56c1a089f90/mimarajos.pdfIn PDF document text
    • http://www.radioemka.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c29422e2756---23390460049.pdfIn PDF document text
    • https://alismobile.co.uk/wp-content/plugins/super-forms/uploads/php/files/ddfbab4be26924f35d75d0337f8539de/dinifori.pdfIn PDF document text
    • http://thanhlamresort.vn/wp-content/plugins/formcraft/file-upload/server/content/files/16079c57f4f320---84706016699.pdfIn PDF document text
    • https://101doctor.com/uploads/ckfiles/files/60b096ce579f0.pdfIn PDF document text
    • https://sailstudy.in/ckfinder/userfiles/files/79697372541.pdfIn PDF document text
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/1c9865b5f069c533da6be916e855c141/vujerodigisib.pdfIn PDF document text
    • http://www.zopfitravel.com/wp-content/plugins/formcraft/file-upload/server/content/files/16073de404bea1---fowidaneroxezeduleruto.pdfIn PDF document text
    • http://tgtech-auto.com/userfiles/file/45643493496.pdfIn PDF document text
    • https://acornschoolcharleston.org/wp-content/plugins/super-forms/uploads/php/files/0f290d0f7bfdd37634447520a06341c2/10471642489.pdfIn PDF document text
    • http://2016montemayorreunion.com/clients/e/e5/e530e98a7ee505477716bae2fe71cdef/File/44836615778.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0001222c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1222C 2880 bytes
SHA-256: 619a44e8b5c2a2d3fc0e18259d8022938ad4f8b30552901bc68dc41c3d0f2ef0
font_01_sfnt_off00012c6a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12C6A 5904 bytes
SHA-256: f1291a1f379c4057fb8f79595c3b546eb2465c24a450377f17f827291311d6ae
font_02_sfnt_off000140ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x140AB 12544 bytes
SHA-256: d7f297eab6ad1225f9615caeb37a424d879d05118a727cf80b571323802e2067