Malicious PDF — malware analysis report

Static analysis result for SHA-256 bac8b1ce7ec8874e…

MALICIOUS

PDF

86.1 KB Created: 2021-07-31 11:59:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 60b76b304fb91316ebd9069180a31cc5 SHA-1: a0f55e3a8c1b07300988887e3daef895dfb484dd SHA-256: bac8b1ce7ec8874ef46e956f044ae81bd7cf1c8e6fff8b6897697e7f9904e823
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It contains a link farm with numerous URLs, many pointing to compromised CMS uploads, suggesting it's used for phishing or distributing further malware. The PDF_SEO_DISPOSABLE_LINK_FARM heuristic indicates a pattern of using disposable hosting for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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=civil+engineering+symbols+and+their+meanings
    • http://www.consorcio.edu.pe/wp-content/plugins/formcraft/file-upload/server/content/files/16084391c8ab0c---26786369139.pdf
    • http://alarcon-v.com/editor_upload_image/file/5976395938.pdf
    • http://fkjz.cn/upload/files/2021/07/202107101820538920.pdf
    • https://cffcommunications.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1/1607b6a79c8429---bevizevilagomaxulepozeniv.pdf
    • http://buffagiuseppeinfissi.com/userfiles/files/95477435557.pdf
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/160cf64125edfa---76013319210.pdf
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/16084f3d6d07f8---36531988664.pdf
    • http://www.gaviprintpack.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608206c308a88---56683060237.pdf
    • https://instalacje-elektryczne.net/ckfinder/userfiles/files/97733856116.pdf
    • http://www.homefacelifters.com/wp-content/plugins/super-forms/uploads/php/files/088066150b3aa7030e7aadd8cf6abd20/68538055456.pdf
    • https://www.criteriainvest.com.br/wp-content/plugins/super-forms/uploads/php/files/ajg0idm2nqnntr0qev36f3vslf/25962067084.pdf
    • https://mindspacepsytherapy.com/upload/ckfinder_temp/files/20210526210502.pdf
    • http://vendingchat.ru/uploads/ckfinder/files/66994989672.pdf
    • https://yarpaket.ru/userfiles/file/satedepovanopudo.pdf
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cd38605831.pdf
    • https://totalyoumovement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b664d01f685---19711568127.pdf
    • http://studiosantese.eu/userfiles/files/1384092115.pdf
    • http://absolutelyneon.com/userfiles/file/66342896716.pdf
    • https://isabellepieman.com/userfiles/file/guxizilunijegetarelo.pdf
    • https://popcouncilinstitute.org/wp-content/plugins/super-forms/uploads/php/files/1d53814729df64e5fbd2f437565b0c5c/rexurinovude.pdf
    • https://travelsafeway.com/userfiles/file/40697662493.pdf
    • http://teplospectr.ru/images/files/26114757381.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ef43.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEF43 16792 bytes
font_01_sfnt_off0001075a.bin
8b357dc3751341f9d098eaaf55560c7d71f5e92b4c1d5674f23ed887b2ee94bc
pdf-font-stream PDF embedded font (sfnt) at offset 0x1075A 11044 bytes
font_02_sfnt_off000120b5.bin
5782bb97e4a5aea410d549f0b87faee7de3432b4663d8946649dda6f3dfb4307
pdf-font-stream PDF embedded font (sfnt) at offset 0x120B5 15796 bytes