Malicious PDF — malware analysis report

Static analysis result for SHA-256 991dcfa07d233407…

MALICIOUS

PDF

84.2 KB Created: 2021-09-17 17:25:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 689ec8a9f3f12d95c935692af2e4487f SHA-1: 2e5bc70cb3e6508806ed7d0798c21f258798a977 SHA-256: 991dcfa07d2334076b7ca5e77afed2ea9683f440bee5a7730e260e60b52f23ab
156 Risk Score

Malware Insights

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

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm pointing to multiple domains, some of which are hosted on compromised WordPress sites. The presence of numerous unknown URLs suggests a redirection mechanism to potentially malicious or phishing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134e08a78825---japexezixijepifajesop.pdf In PDF document text
    • http://dison.cn/filespath/files/20210917120356.pdfIn PDF document text
    • https://ceiling.holcom.vn/webroot/img/files/59717972426.pdfIn PDF document text
    • http://dieukhactransam.com/uploads/files/miwamapukisonawomuwupanej.pdfIn PDF document text
    • http://xn--80aagkbrca3apkgkee0a1bi.xn--p1ai/ckfinder/userfiles/files/zijifu.pdfIn PDF document text
    • https://digireg.sk/upload/31263230407.pdfIn PDF document text
    • https://www.espymetcalf.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fbf322b2d3---mijorajus.pdfIn PDF document text
    • http://adfaveo.com/image/files/20210915_221519.pdfIn PDF document text
    • https://madspot.dk/ckfinder/userfiles/files/9903550700.pdfIn PDF document text
    • http://yummyschool.com/_UploadFile/Images/file/91326873606.pdfIn PDF document text
    • https://jooli.ru/ckfinder/userfiles/files/lemisenip.pdfIn PDF document text
    • https://aiaciran.org/cache/fck_files/file/fidizekuro.pdfIn PDF document text
    • http://namhungholdings.com/uploads/ckfinder/files/76112425076.pdfIn PDF document text
    • http://instant-image.net/UserFiles/Site/File/80085078628.pdfIn PDF document text
    • http://signauction.net/userfiles/file/293147229.pdfIn PDF document text
    • https://www.elementstraining.co.uk/wp-content/plugins/super-forms/uploads/php/files/76rgbl9r4mce7or8kguluavd49/15802586384.pdfIn PDF document text
    • http://farmaciafasolis.eu/userfiles/files/xidozakikepa.pdfIn PDF document text
    • https://vasantviharproperties.com/userfiles/file/65610930544.pdfIn PDF document text
    • https://sipare.com.ar/wp-content/plugins/super-forms/uploads/php/files/nilgh2vkg3t66rml6hp1o3f8nc/vaxefekozafo.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161385fa553d62---58961277591.pdfIn PDF document text
    • http://tidomusica.com/uploads/files/202109011449437517.pdfIn PDF document text
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161328cd376cf9---68456530318.pdfIn PDF document text
    • https://oancora.com/ckfinder/files/wagowusavefonageno.pdfIn PDF document text
    • http://pozitron-s.ru/userfiles/file/lapupabimisuwipo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=woocommerce+android+app+nulledPDF 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_off0000e3b6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE3B6 18316 bytes
SHA-256: f74179460e1bcb13931309a0ff9729e18ad279eb51e7aa2c0e216bc729aca09c
font_01_sfnt_off00011334.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11334 10500 bytes
SHA-256: e13da95d9342d31a4e8d9caf8c58b885f6bebfd4e7626bddd3a53d235ebeef24
font_02_sfnt_off00012af7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12AF7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1