Malicious PDF — malware analysis report

Static analysis result for SHA-256 4bc8c8981e366c29…

MALICIOUS

PDF

41.6 KB Created: 2020-09-10 23:56:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 38c763e538a84f6b4daf0d6e4c099464 SHA-1: 8364114373b688b8af2357606e657dd864fae1b1 SHA-256: 4bc8c8981e366c29ad2bc4169550e3de6447f2ea724801ef9583648ea5b135a1
152 Risk Score

Malware Insights

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

The PDF contains numerous embedded links, with a critical heuristic firing for a malicious redirector. The document body, though heavily obfuscated, contains text related to 'math worksheets' and includes the primary malicious URL. The ML classifier also strongly indicated maliciousness. The primary attack vector appears to be a lure to a malicious redirector disguised as educational content.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 4

  • PDF links to known malicious redirector infrastructure critical PDF_MALICIOUS_REDIRECTOR_LINK
    PDF contains a clickable URI to redirector infrastructure used by a known malicious PDF SEO/adware delivery campaign. These documents typically rely on user interaction and redirect chains rather than a PDF parser vulnerability.
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://ttraff.me/wix?keyword=math+worksheets+for+kindergarten+graders
    • http://files.sundanceretrievers.com/uploads/1/3/0/7/130740065/ea06de436e3771f.pdf
    • http://files.englishservicesforscientists.com/uploads/1/3/2/3/132303269/3a6c72bb1c0.pdf
    • http://vapigupi.saintgregorysileby.org/uploads/1/3/1/3/131380934/kotebogisarisaf-folijoma-rojugizaj.pdf
    • https://cdn.shopify.com/s/files/1/0429/2627/6775/files/90335245234.pdf
    • https://cdn.shopify.com/s/files/1/0435/0862/9659/files/kojukunuxupebe.pdf
    • https://cdn.shopify.com/s/files/1/0431/2812/7650/files/antebellum_era_reform_movements_such_as_abolitionism.pdf
    • https://cdn.shopify.com/s/files/1/0433/5190/0310/files/bamovefipawukag.pdf
    • https://cdn.shopify.com/s/files/1/0434/3519/6568/files/23204418200.pdf
    • https://cdn.shopify.com/s/files/1/0435/5643/8165/files/20843085710.pdf
    • https://cdn.shopify.com/s/files/1/0427/8029/5334/files/1899560536.pdf
    • https://static.usrfiles.com/ugd/f1d680_3e84a162d98249e3ae185f6bb09eadef.pdf
    • https://static.usrfiles.com/ugd/c068f8_1462f8893c104999af62684622f61b50.pdf
    • https://static.usrfiles.com/ugd/0adedf_cc7473b32cfe4d139d0cef70368b0100.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/

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00006527.bin
38b2d832b60509caa1e55a676d42bb6c8382a7888e8c8630371d1f01b89e71a4
pdf-font-stream PDF embedded font (sfnt) at offset 0x6527 5296 bytes
font_01_sfnt_off00007746.bin
150331e0fe867e670130970a42356c46e05fde8de14ec663e1a21de41b90b9f3
pdf-font-stream PDF embedded font (sfnt) at offset 0x7746 10096 bytes