Malicious PDF — malware analysis report

Static analysis result for SHA-256 5a1a13b5b2aa23a0…

MALICIOUS

PDF

97.1 KB Created: 2021-08-08 05:18:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 8db705d1f86bdc936ffa04f3a26e8a18 SHA-1: 5a92dc987a21a66bbb001e4be58cca6232cdcb20 SHA-256: 5a1a13b5b2aa23a061b3ceb1242e7e2b7d4190bfb75b1d2bfcbcfff1f8e6ddca
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, indicating it likely contains malicious content. Heuristics identified it as a link farm, with many URLs pointing to compromised or disposable hosting, suggesting a phishing or malware distribution scheme. The document body is heavily obfuscated and unreadable, providing no direct clues to its intent beyond what the heuristics suggest.

Machine Learning

  • Nyx PDF Classifier malicious score 0.7644

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
  • PDF differential parser failed info PDF_DIFFERENTIAL_PARSE_FAILED
    The cross-check parser (pdfminer.six) failed on this file: PDF differential parser failed: PDFSyntaxError. Static heuristics still ran and any of their findings above are valid; only the differential cross-check signal is missing.
  • 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://85097781.com/upload/files/buxogodotazavipizo.pdf In PDF document text
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9dbbe549be---vivivigurepulijej.pdfIn PDF document text
    • http://asbu.net/uploads/FCK_files/file/debefezezujop.pdfIn PDF document text
    • http://www.seja.lv/assets/ckfinder/core/connector/php/uploads/files/zujemakus.pdfIn PDF document text
    • https://riverasphotovideo.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609df5e4f0ec2---27015863984.pdfIn PDF document text
    • https://dm288.rs/slicice/file/bitibitukuwamuturarufajox.pdfIn PDF document text
    • http://sammyuriasproperties.com/userfiles/files/metini.pdfIn PDF document text
    • https://humanistbeauty.com/wp-content/plugins/super-forms/uploads/php/files/kfkjf7uvqerq5fvmd9tdptt0fd/zadogi.pdfIn PDF document text
    • http://cp-tournament.org/ckfinder/userfiles/files/finuzi.pdfIn PDF document text
    • http://bestapp4u.com/admin/uploadedfiles/file/9732211444.pdfIn PDF document text
    • http://www.tif.cn/wp-content/plugins/super-forms/uploads/php/files/vvp6lelivq43b7lq525d0e30oc/bugewet.pdfIn PDF document text
    • http://noithattamphuong.com/upload/files/xegiradew.pdfIn PDF document text
    • https://securitydm.rs/slicice/file/92916001832.pdfIn PDF document text
    • https://ytdrive.com/CKEdit/upload/files/92642704801.pdfIn PDF document text
    • http://pavcargo.ru/wp-content/plugins/super-forms/uploads/php/files/5c572958e880b64f47ea8d4c712be37a/27236648874.pdfIn PDF document text
    • http://www.hotel-margherita.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606f634c6c57a---64842690899.pdfIn PDF document text
    • https://www.mclarenpress.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b0ee01b611---xikediwesex.pdfIn PDF document text
    • http://szyldkj.com/luodan/images/userfiles/file/69767408128.pdfIn PDF document text
    • https://dsodrecital.com/wp-content/plugins/formcraft/file-upload/server/content/files/16071adfb94d34---walumoso.pdfIn PDF document text
    • https://bfull.ru/uploads/files/beviwujedo.pdfIn PDF document text
    • https://hrmconsulting.biz/upload/files/gasorezodonumabujan.pdfIn PDF document text
    • http://daphongthuyhueminh.com/uploads/image/files/83252948933.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3CAf4wW3hvY/uplcv?utm_term=m%C3%A9t%C3%A9o+et+climat+svt+5eme+evaluation+pass+educationPDF link annotation
    • 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_off00011abb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11ABB 11020 bytes
SHA-256: a4840c23ec2d603036056b6189ed21be367df07af85b0543d87a774bc3834dfd
font_01_sfnt_off00013424.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13424 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00014c36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14C36 20384 bytes
SHA-256: 0e4712d9da8fa50842e886c71a49ce8002204b6079d4adc858cf556049bfb59d