Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8552a87e5f6e697…

MALICIOUS

PDF

78.1 KB Created: 2021-09-16 15:50:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 8e44e58ae61689b0e47770cc3998fec0 SHA-1: 0e0209908dc9b71aaacfc18798996f42d830be63 SHA-256: f8552a87e5f6e6979c5a56f21d31cd6912f41cb40a6007d7da5e3ca3e29b1c6e
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware delivery through these links. The presence of multiple link farm heuristics further supports this assessment.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://smidgel.ru/uplcv?utm_term=call+recording+app+pro+apk PDF link annotation
    • http://www.radio-kum.si/data/files/wibelijulivumovajor.pdfIn PDF document text
    • http://mopron.ru/upload/files/tebowan.pdfIn PDF document text
    • http://andlupa.com/userfiles/file/3587005238.pdfIn PDF document text
    • https://www.beadvised.co.uk/wp-content/plugins/super-forms/uploads/php/files/457d943fd1599c11aad81dd8cec91ca9/83826636255.pdfIn PDF document text
    • https://dollarplus98.com/images/upload/files/94960348094.pdfIn PDF document text
    • http://uniroll.pl/user_images/file/68362730813.pdfIn PDF document text
    • http://webinaris.blog/ckfinder/userfiles/publics/files/foritoduwagab.pdfIn PDF document text
    • http://gavionescodeinsa.com/userfiles/41578602373.pdfIn PDF document text
    • https://ycb.one/pro_pic/files/navugegozevuxag.pdfIn PDF document text
    • https://nic-irq.com/userfiles/files/tawakofipuxifazobikadugef.pdfIn PDF document text
    • https://defi128.com/userfiles/files/xovovarofazexapes.pdfIn PDF document text
    • https://markzone.az/wp-content/plugins/super-forms/uploads/php/files/esoud4qfgbenhgk33b9k840pus/jonajosezukuvik.pdfIn PDF document text
    • https://corpus.bg/files/fck/file/27497462212.pdfIn PDF document text
    • https://dotcomtravelegypt.com/userfiles/files/78078519069.pdfIn PDF document text
    • http://autosoftware.company/autoresponders_images/files/dupomanu.pdfIn PDF document text
    • http://www.bridalchapel.com/wp-content/plugins/formcraft/file-upload/server/content/files/161402fc3e5c84---wanowekotenisanugud.pdfIn PDF document text
    • http://coolscape.info/images/files/jekimafejowejufak.pdfIn PDF document text
    • http://charugarware.com/DEVELOPMENT/charu_garware/uploaded/userfiles/file/xaguwubofi.pdfIn PDF document text
    • https://sikdercollegeofpharmacy.com/scp/ckfinder/uploads/userfiles/files/nufujixuk.pdfIn PDF document text
    • http://axiomestates.com/userfiles/file/57111543779.pdfIn PDF document text
    • http://huile-de-nigelle.info/userfiles/file/jaritolafuluvasarus.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
font_00_sfnt_off0000bc4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBC4F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d466.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD466 10544 bytes
SHA-256: 631ba72975a767a77ca247b88e8b2fe3ac93eea6943c95725fac6e24b71bf264
font_02_sfnt_off0000ec3b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC3B 1680 bytes
SHA-256: 6c08887b596ecb472c5a0482df8c2f828d83fc5b5d16111ed0caa1fced1b35dc
font_03_sfnt_off0000f433.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF433 21732 bytes
SHA-256: dcdd0822843e4ab84553d207d809fdceab0b4faff4beb150e917fcdda28908e0