Malicious PDF — malware analysis report

Static analysis result for SHA-256 4c81f7939b3b98af…

MALICIOUS

PDF

82.6 KB Created: 2021-06-27 21:58:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-08-20
MD5: e5b202ccdb53ac420c7fa9d0f2ffffcc SHA-1: 6ffd7fdeee529541c120fdd70b72eec5289e83f2 SHA-256: 4c81f7939b3b98af757f4a3e67aa498b0c24ede1fa9658bc9975b116e673220e
156 Risk Score

Malware Insights

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

The PDF document contains a large number of embedded URLs, many of which point to compromised CMS upload directories or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery through these links. No scripts were extracted, and the document body was unreadable, so the primary threat vector appears to be the link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9931

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://philabc.ru/uplcv?utm_term=segment+meaning+in+malayalam PDF link annotation
    • https://invest.pl/userfiles/file/vojulukawifijepusupo.pdfIn PDF document text
    • https://rhdplumbing.com/wp-content/plugins/super-forms/uploads/php/files/40edf636a95d05fd6fe730f1469a78be/jaxegabezit.pdfIn PDF document text
    • https://www.tessilgiada.it/wp-content/plugins/formcraft/file-upload/server/content/files/1609ce503f2c2f---4055415519.pdfIn PDF document text
    • https://noddy.nu/images/file/kuwupagapanuwesusuza.pdfIn PDF document text
    • http://hillsdalehorseboarding.com/ckfinder/userfiles/files/60706799359.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a922472cf17---81252871492.pdfIn PDF document text
    • http://vasvaripalmuzeum.hu/upload/file/8974012221.pdfIn PDF document text
    • https://cedarcreeksauce.com/wp-content/plugins/super-forms/uploads/php/files/8826d14a50b133a653b7f9b55f7d83eb/zidajoxazafu.pdfIn PDF document text
    • http://originalcheck.it/public/img_admin/file///xotuvifud.pdfIn PDF document text
    • https://www.nestroots.com/wp-content/plugins/super-forms/uploads/php/files/u995hs4c3jrr8h16hg93igldo4/sivuwonixigitewizakipelu.pdfIn PDF document text
    • http://backyardreleaf.ca/clients/6/6a/6a4eaaf8452764cb6fc14c9064ed0c71/File/texegalimovunusipebe.pdfIn PDF document text
    • https://rrvchefs.com/wp-content/plugins/super-forms/uploads/php/files/ddaf07ccfc08448347a4d945e277c5a6/10409594045.pdfIn PDF document text
    • https://dubaimotorcycletours.com/uploaded_images/files/31683469405.pdfIn PDF document text
    • http://asesoriagarpe.com/wp-content/plugins/formcraft/file-upload/server/content/files/16098a4f51c825---xefolulud.pdfIn PDF document text
    • http://auburn-properties.com/userfiles/files/kutagukuzipafobekebowujum.pdfIn PDF document text
    • https://aashianarealty.com/file/viwubowavalovutusagogidij.pdfIn PDF document text
    • https://www.birdandwildlifeteam.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606feaccc39ab---38289170149.pdfIn PDF document text
    • https://flexrocksrollovers.com/wp-content/plugins/super-forms/uploads/php/files/e0q3m30lbt5ej2empbd0ogbs57/5546471363.pdfIn PDF document text
    • http://reszke.pl/fckeditor/editor/filemanager/connectors/php/file/luxozubopopejadifubetebe.pdfIn PDF document text
    • https://djhelaly.com/wp-content/plugins/super-forms/uploads/php/files/9911a44ea11bfd7dbf4fb4adf1e6d035/domolura.pdfIn PDF document text
    • http://hengtaixin.com/HangShun/ckfinder/userfiles/files/losogemetefu.pdfIn PDF document text
    • https://www.psalighting.com/wp-content/plugins/super-forms/uploads/php/files/bf1747b7dfe4341034dbc6c28da104d9/duvol.pdfIn PDF document text
    • http://kozelskadm.ru/files/uploads/files/41056478998.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off000102ae.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0x102AE 19204 bytes
SHA-256: b425ae4a1b385913bdc1b421f2bf67f195440a56c9c79c3cac6b9761764effd9
font_00_sfnt_off0000c0eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC0EB 16504 bytes
SHA-256: 71630c695e3aa870c3ed21f2440e2eb0fe3f8c359275a95004e7ce1714e6089f
font_01_sfnt_off0000ebaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEBAA 10252 bytes
SHA-256: f8a8b403811d3adadf789dad5ac2f3d1a55013e712677d99f839cf90f267d2af
font_03_sfnt_off000121ae.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121AE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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