Malicious PDF — malware analysis report

Static analysis result for SHA-256 4376f720ded22bce…

MALICIOUS

PDF

83.2 KB Created: 2021-10-04 21:18:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: a111ccaf29d8ff6e297ef2f18d61f84d SHA-1: e8165b20c2987ce44fc2ecfe51aa98e0b5af0428 SHA-256: 4376f720ded22bce7fd69d449bce9a8e36c52f6529198b21e6234aa91b8915bf
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF contains a large number of embedded URLs, many of which point to other PDF files hosted on various domains. Several heuristics indicate that these are link farms, with some links pointing to compromised WordPress uploads. The ML classifier also strongly flagged this PDF as malicious. The document body is heavily obfuscated and unreadable, providing no direct clues about its intent beyond the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 5

  • 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://nomylo.ru/uplcv?utm_term=process+control+designing+processes+and+control+systems+for+dynamic+performance+solution+manual PDF link annotation
    • http://a-pluset.com/userfiles/feronomiz.pdfIn PDF document text
    • http://theurbanbazzaar.com/userfiles/file/wuvakolevomanafulowe.pdfIn PDF document text
    • http://4rrecycle.com/files/file/77195401947.pdfIn PDF document text
    • http://prospekt-rostov.ru/ckfinder/userfiles/files/rajuvaraxij.pdfIn PDF document text
    • https://menokatea.in/ckfinder/userfiles/files/vizugirewunawofap.pdfIn PDF document text
    • https://prtl.pl/userfiles/file/mivaposo.pdfIn PDF document text
    • https://himalmanpower.com/ckfinder/userfiles/files/xobobijosar.pdfIn PDF document text
    • http://www.rebranded.tv/wp-content/plugins/formcraft/file-upload/server/content/files/1615a9ee69d79a---jazim.pdfIn PDF document text
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/ibn2epgfts4m5fo33prcs1tn3c/waruwegogofujowovonad.pdfIn PDF document text
    • http://cokhihoaiduc.com/uploads/files/71708703957.pdfIn PDF document text
    • http://agierresrl.it/userfiles/files/55504044097.pdfIn PDF document text
    • http://rebeccaosborne.com/uploads/20349214225.pdfIn PDF document text
    • https://holyfamilyhospitals.com/ckfinder/userfiles/files/rejaxexuvodowulegisaluran.pdfIn PDF document text
    • https://sunkamalzemecilik.com/userfiles/file/37579792977.pdfIn PDF document text
    • http://brandiassociati.it/userfiles/file/bufelovaxalid.pdfIn PDF document text
    • http://automsystem.com/UploadFile/file/20210924085419688.pdfIn PDF document text
    • https://lsv-wittlage.de/ckfinder/userfiles/files/47499962200.pdfIn PDF document text
    • http://boldogelet.hu/media/bawikegugu.pdfIn PDF document text
    • http://dentherapia.hu/files/file/89481226209.pdfIn PDF document text
    • http://huabulaw.com/uploadpic/2021-9/file/2021092720451973499.pdfIn PDF document text
    • https://www.dekleinewerf.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16146b1b34357a---63274352805.pdfIn PDF document text
    • http://globalcenterhotels.com/bot/ckfinder/uf/files/31494726052.pdfIn PDF document text
    • http://jyy.jp/ckfinder/userfiles/files/20210917_182524.pdfIn PDF document text
    • http://hzxf.com/images/upload/File/nagokatov.pdfIn 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://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_off0000dec2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDEC2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f6d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF6D4 17612 bytes
SHA-256: 3190f20a71361b7e3b411f06632dcf192b239ab06f64e580dd9973d6577f3b81
font_02_sfnt_off00012437.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12437 11180 bytes
SHA-256: 47bd2b490a821d123b3cb102adb1163ff96c9a44accec8119eb3b938b14112a1