Malicious PDF — malware analysis report

Static analysis result for SHA-256 812398aa1f0a878c…

MALICIOUS

PDF

81.7 KB Created: 2021-09-25 20:17:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: c46026dba33f6cf4dc62abc6f12bd58d SHA-1: 2885f843d8ea560481f4d7dda2160ee6b976d15b SHA-256: 812398aa1f0a878c310172dd33bbbb5396424a1290ac9ec24f940766d9c94bbd
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to other PDF files hosted on distinct domains, indicating a link farm. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic further supports this, suggesting the document is used for SEO manipulation or to distribute further malicious content. No scripts were extracted, but the overall structure and heuristics point to a phishing or content distribution scheme.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9933

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://minhkygroup.com/luutru/files/15050855092.pdf In PDF document text
    • http://szymonadamczyk.pl/uploads/fck/file/nexuw.pdfIn PDF document text
    • https://www.bouldersudbury.org/wp-content/plugins/formcraft/file-upload/server/content/files/1614dd1e1d2c8f---73556588182.pdfIn PDF document text
    • http://lnv-cnc.com/userfiles/file/rokolosizitonex.pdfIn PDF document text
    • https://bistakalikotenetwork.com/userfiles/file/vawopujilamokaliwekexu.pdfIn PDF document text
    • http://chinajnbt.com/images/upload/File/bufukolosupijekagefures.pdfIn PDF document text
    • https://equinox-e.com/upload/files/44015027138.pdfIn PDF document text
    • https://nezamirekhaseafoods.com/userfiles/file/5888574201.pdfIn PDF document text
    • http://filtrydokoparek.pl/img/all/52069091265.pdfIn PDF document text
    • https://justforjetscatering.com/userfiles/image/files/pikuwonamedezazamu.pdfIn PDF document text
    • http://delifarm.com/images/file/zobeferaxesewaxepo.pdfIn PDF document text
    • http://tsradviseurs.nl/mailing/images/photo/file/18138781090.pdfIn PDF document text
    • http://kdwatch.net/upload/files/2021090610005111.pdfIn PDF document text
    • https://www.ccs-corporation.com/ckfinder/userfiles/files/tilipopile.pdfIn PDF document text
    • http://xn--80aer5aza.xn--c1acndkmcarx.xn--p1ai/ckfinder/userfiles/files/16120199726.pdfIn PDF document text
    • https://mylin.in/ckeditor/ckfinder/userfiles/files/lokakeputez.pdfIn PDF document text
    • http://chonburi33.com/userfiles/file/53332707200.pdfIn PDF document text
    • https://officialbacknumber.org/editor_up/wemowozajakitefedatu.pdfIn PDF document text
    • https://lllk.ru/wp-content/plugins/super-forms/uploads/php/files/380341d28954bbd1b65209c86661bd1f/gulujinavuzu.pdfIn PDF document text
    • http://mbeautyconcept.com/upload/content_images/file/zuvijelubolejagika.pdfIn PDF document text
    • http://kaztelcom.kz/ckfinder/userfiles/files/tasofipawowudasuxizesipi.pdfIn PDF document text
    • https://brothers-music.com/ckfinder/userfiles/files/86781248302.pdfIn PDF document text
    • https://eric-parnes.shortex.com/ckfinder/userfiles/files/57975624887.pdfIn PDF document text
    • http://kepco-group.com/uploaded_files/userfiles/files/nanokikidagatinofuwiv.pdfIn PDF document text
    • http://bosch-elektronarzedzia.pl/catalog/file/61757290103.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=wifi+bruteforcer+apkPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bd68.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD68 16240 bytes
SHA-256: bc86923d43351b01c5d0eb8bcf3a4bac74fbcf581cbb42a4c10de5fa5ee30687
font_01_sfnt_off0000d36d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD36D 21704 bytes
SHA-256: 760b11be2b801c565de7a280d86c6177573f43eeba1cc6ca3f6b2b625fe1f824
font_02_sfnt_off000108e1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108E1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off000120f8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x120F8 10480 bytes
SHA-256: 052967b855408bb4630c15187eb17d4ed20a16b536c96755fa106f8ec23f8bde